UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 


COLLEGE  OF  AGRICULTURE 

AGRICULTURAL  EXPERIMENT  STATION 

BERKELEY.  CALIFORNIA 


THE  HOUSE  ELY  IN  ITS  RELATION 
TO  PUBLIC  HEALTH 


By  WILLIAM  B.  HERMS 


BULLETIN  No.  215 

(Berkeley,  Cal.,  May,  1911) 


SACRAMENTO 
W.    W.    SHANNON      -      -      -      -      SUPERINTENDENT    STATE    PRINTING 

1911 


EXPERIMENT  STATION  STAFF. 

E.  J.  Wickson,  M.A.,  Director  and  Horticulturist. 

E.  W.  Hilgard,  Ph.D.,  LL.D.,  Chemist  (Emeritus). 

W.  A.  Setchbll,  Ph.D.,  Botanist. 

Lerot  Anderson,  Ph.D.,  Dairy  Industry  and  Superintendent  University  Farm  Schools. 

M.  E.  Jaffa,  M.S.,  Nutrition  Expert,  in  charge  of  the  Poultry  Station. 

R.  H.  Loughridge,  Ph.D.,  Soil  Chemist  and  Physicist  (Emeritus). 

C.  W.  Wood  worth,  M.S.,  Entomologist. 

Ralph  E.  Smith,  B.S.,  Plant  Pathologist  and  Superintendent  of  Southern  California 

Pathological  Laboratory  and  Experiment  Station. 
G.  W.   Shaw,  M.A.,  Ph.D.,  Experimental  Agronomist  and  Agricultural  Technologist, 

in  charge  of  Cereal  Stations. 

E.  W.  Major,  B.Agr.,  Animal  Industry,  Farm  Manager,  University  Farm,  Davis. 

F.  T.  Bioletti,  B.S.,  Vitlculturist. 

B.  A.  Etcheverry,  B.S.,  Irrigation  Expert. 

George  E.  Colby,  M.S.,  Chemist  (Fruits,  Waters,  and  Insecticides),  in  charge  of 
Chemical  Laboratory. 

H.  J.  Quayle,  M.S.,  Assistant  Entomologist,  Plant  Disease  Laboratory,  Whittier. 

W.  T.  Clarke,  B.S.,  Assistant  Horticulturist  and  Superintendent  of  University  Exten- 
sion in  Agriculture. 

H.  M.  Hall,  Ph.D.,  Assistant  Botanist. 

C.  M.  Haring,  D.V.M.,  Assistant  Veterinarian  and  Bacteriologist. 
John  S.  Burd,  B.S.,  Chemist,  in  charge  of  Fertilizer  Control. 

E.  B.  Babcock,  B.S.,  Assistant  Agricultural  Education. 
W.  B.  Herms,  M.A.,  Assistant  Entomologist. 

J.  H.  Norton,  M.S.,  Assistant  Chemist,  in  charge  of  Citrus  Experiment  Station,  River- 
side. 
W.  T.  Horne^-B.S.,  Assistant  Plant  Pathologist. 

J.  E.  Corr,  Ph.D.,  Assistant  Pomologist,  Plant  Disease  Laboratory,  Whittier. 
C.  B.  Lipman,  Ph.D.,  Soil  Chemist  and  Bacteriologist. 
R.  E.  Mansell,  Assistant  in  Horticulture,  in  charge  of  Central  Station  grounds. 

A.  J.  Gaumnitz,  M.S.,  Assistant  in  Cereal  Investigations,  University  Farm,  Davis. 

E.  H.  Hagemann,  Assistant  in  Dairying,  Davis. 

B.  S.  Brown,  B.S.A.,  Assistant  in  Horticulture,  University  Farm,  Davis. 

F.  D.  Hawk,  B.S.A.,  Assistant  in  Animal  Industry. 

J.  I.  Thompson,  B.S.,  Assistant  in  Animal  Industry,  Davis. 

R.  M.  Roberts,  B.S.A.,   Field  Assistant  in  Viticulture,   University  Farm,  Davis. 

J.  C.  Bridwell,  B.S.,  Assistant  Entomologist. 

C.  H  McCharles,  B.S.,  Assistant  in  Agricultural  Chemical  Laboratory. 
N.  D.  Ingham,  B.S.,  Assistant  in  Sylviculture,  Santa  Monica. 

E.  H.  Smith,  M.S.,  Assistant  Plant  Pathologist. 
T.  F.  Hunt,  B.S.,  Assistant  Plant  Pathologist. 

C.  O.  Smith,  M.S.,  Assistant  Plant  Pathologist,  Plant  Disease  Laboratory,  Whittier. 

F.  L.  Yeaw,  B.S.,  Assistant  Plant  Pathologist,  Vacaville. 
F.  E.  Johnson,  B.L.,  M.S.,  Assistant  in  Soil  Laboratory. 
Charles  Fuchs,  Curator  Entomological  Museum. 

P.  L.  Hibbard,  B.S.,  Assistant  Fertilizer  Control  Laboratory. 

L.  M.  Davis,  B.S.,  Assistant  in  Dairy  Husbandry,  University  Farm,   Davis. 

L.  Bonnet,  LA.,  Assistant  in  Viticulture. 

S.  S.  Rogers,  B.S.,  Assistant     Plant  Pathologist,  Plant  Disease  Laboratory,  Whittier. 

B.  A.  Madson,  B.S.A.,  Assistant  in  Cereal  Laboratory. 

Walter  E.  Packard,  M.S.,  Field  Assistant  Imperial  Valley  Investigation,  El  Centre 

M.  E.  Stover,  B.S.,  Assistant  in  Agricultural  Chemical  Laboratory. 

P.  L.  McCreary,  B.S.,  Laboratory  Assistant  in  Fertilizer  Control. 

E.  E.  Thomas,  B.S.,  Assistant  Chemist,  Plant  Disease  Laboratory,  Whittier. 

Anna  Hamilton,  Assistant  in  Entomology. 

Mrs.  D.  L.  Bunnell,  Secretary  to  Director. 

W.  H.  Volck,  Field  Assistant  in  Entomology,  Watsonville. 

E.  L.  Morris,  B.S.,  Field  Assistant  in  Entomology,  San  Jose. 

J.  S.  Hunter,  Field  Assistant  in  Entomology,  San  Mateo. 

J.  C.  Roper,  Patron  University  Forestry  Station,  Chico. 

J.  T.  Bearss,  Foreman  Kearney  Park  Station,  Fresno. 

E.  C.  Miller,  Foreman  Forestry  Station,  Chico. 


CONTENTS. 


Page. 
Introduction. 

Insects  and  disease  transmission ;  medical  entomology 513 

Economic  Importance. 

Losses  occasioned  by  mosquitoes ;   malaria  and  real  estate ;   typhoid  fever 

losses;  cost  of  temporary  preventive  measures 513 

Methods  of  Disease  Transmission. 

Direct  and  indirect  methods ;  dependent  upon  structure  of  mouthparts ;  dis- 
tinctions in  habit  and  ecology  of  pathogenic  bacteria  and  protozoa 514 

What  is  the  House  Fly? 

Relation  to  other  flies 517 

Life  History  and  Development. 

Number  of  eggs  deposited ;  suitable  situation  for  egg  deposition ;  estimate  of 
number  of  larvae  developing  in  a  manure  pile ;  larval  growth ;  prepupal 
period ;  pupal  period ;  time  required  for  life  cycle ;  size  of  the  adult  fly ; 

distribution  of  sexes ;  relative  number  of  house  flies  in  dwellings 518 

Relation  of  House  Fly  to  Disease  Transmission. 

Probably  not  a  necessary  intermediate  host  of  pathogenic  organisms ;  im- 
portance of  structure  and  habit ;  not  a  valuable  scavenger ;  experimental 

evidence  of  transmission 523 

Typhoid  Fever. 

Channels  of  infection;  evidence  of  transmission  by  house  fly 528 

Dysentery. 

Varieties  of;  transmission 529 

Summer  Diarrhea  in  Infants. 

Infection  530 

Tuberculosis. 

Channels  of  infection ;  infection  by  way  of  the  alimentary  tract ;  pre- 
cautions   : 530 

Asiatic  Cholera. 

Methods  of  transmission 532 

Other  Diseases  Probably  Transmitted. 

Certain  forms  of  Opthalmia ;  Leprosy,  Erysipelas;  Smallpox 532 

Objections  Met. 

Opposition ;  parasitism,  abstracts  from  letter 532 

Essentials  of  Control. 

Prevention  planned  along  scientific  lines;  house  fly  can  be  controlled;  co- 
operation needed ;  open  manure  piles  must  be  abolished  -,  fly-tight  recep- 
tacles ;  permanent  preventive  measures ;  insecticides ;  larvae  ;  adult  flies ; 
carrying  out  preventive  measures 539 

Indoor  Work — the  Adult  Fly 539' 

Community- Wide  Campaigns. 

How  begun ;  newspaper  agitation ;  work  of  Department  of  Public  Health 

and  Safety 541 

Literature  Cited. 


THE  HOUSE  ELY  IN  ITS  RELATION  TO  PUBLIC  HEALTH 


i. 

INTRODUCTION. 

The  importance  of  the  study  of  insects  in  many  departments  of  human 
interest  is  being  the  more  fully  recognized  as  science  reveals  the  facts 
of  interrelationships,  both  advantageous  and  destructive.  Mosquitoes 
and  flies  have  for  centuries  past  been  looked  upon  as  a  source  of  extreme 
annoyance  to  the  human  family,  but  that  these  insects  might  be  trans- 
mitters of  disease  was  hardly  even  suspected  until  the  latter  part  of  the 
last  century.  (King,  '83.)  That  insects  and  arachnids  of  a  given 
species  might  be  the  sole  transmitters  of  a  specific  disease,  and,  what  is 
more,  a  necessary  factor,  inasmuch  as  these  forms  serve  as  intermediate 
host,  was  not  considered  seriously  until  the  latter  five  years  of  the  last 
and  the  beginning  of  this,  the  twentieth  century.  (See  sundry  papers 
by  A.  Laveran,  R.  Ross,  R.  Koch,  P.  Manson,  B.  Grassi  et  al. ;  all  on 
malaria  and  its  causative  organism. )  There  have  now  appeared  literally 
hundreds  of  isolated  papers  relating  to  the  transmission  of  disease  by 
insects,  and  we  are  at  this  time  obliged  to  recognize  the  new  subject 
which  we  term  Medical  Entomology.  (Herms,  '09<1)  This  field  embraces 
phases  of  the  study  of  medicine,  mainly  the  etiology  and  pathology  of 
such  diseases  as  malaria,  yellow  fever,  sleeping  sickness,  filariasis,  etc., 
of  bacteriology,  inasmuch  as  the  causative  germ  must  be  studied,  and  of 
entomology,  inasmuch  as  the  mouthparts  and  other  structures  of  the 
insect  must  be  known  as  well  as  its  systematic  relationships. 

There  need  be  no  question  as  to  the  justification  of  our  investigations 
in  this  ever  broadening  field  when  the  economic  loss  to  mankind  is  con- 
sidered. One  need  but  consult  the  timely  and  valuable  paper  by  Dr.  L. 
0.  Howard  ('09)  entitled  "Economic  loss  to  the  people  of  the  United 
States  through  insects  that  carry  disease,"  to  be  impressed  with  this 
enormous  loss.  Doctor  Howard  states,  "Entirely  aside  from  the  loss 
occasioned  by  mosquitoes  as  carriers  of  specific  diseases,  their  abundance 
brings  about  a  great  monetary  loss  in  other  ways.  Possibly  the  greatest 
of  these  losses  is  in  the  reduced  value  of  real  estate  in  mosquito-infested 
regions,  since  these  insects  render  absolutely  uninhabitable  large  areas 
of  land  available  for  suburban  homes,  for  summer  resorts,  for  manufac- 
turing purposes,  and  for  agricultural  pursuits."  (See,  also,  Herri ck, 
'03.)  The  expense  to  the  United  States  incurred  in  the  purchase  of  fly 
traps,  sticky  fly  paper,  fly  poison  and  the  like,  must  certainly  exceed 


514 


UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION. 


two  millions  of  dollars  annually,  while  Howard  ('09)  estimates  the  cost 
of  screening  at  over  ten  millions  of  dollars  per  annum.  The  commercial 
value  of  a  human  life  is  estimated  on  the  average  at  three  thousand 
dollars.  The  decrease  in  the  vital  assets  of  this  country  through  typhoid 
fever  alone  (much  of  which  is  transmitted  by  the  house  fly  or  typhoid 
fly)  amounts  to  $350,000,000.    (Felt,  '09.) 

The  California  State  Board  of  Health  in  "The  California  Sanitation 
Exhibit,  1909,"  writes  as  follows:  "California  loses  annually  5,000 
citizens  from  tuberculosis,  500  from  typhoid  fever,  and  500  more  from 
diseases  caused  by  infected  milk  and  food  supply.  This  means  that 
approximately  one  out  of  every  five  residents  eventually  dies  from  one 
of  these  diseases  contracted  through  personal  or  public  failure  to  provide 
the  essentials  of  sanitary  environment.  *  '*  *  The  six  thousand 
deaths  which  could  be  prevented  by  the  enforcement  of  public  health 
laws  represent  an  annual  loss  of  $18,000,000  per  year  to  the  State,  in 
addition  to  the  personal  and  social  losses  which  can  not  be  estimated  in 
terms  of  money. ' ' 

Malaria,  typhoid  fever,  yellow  fever,  bubonic  plague,  sleeping  sick- 
ness, cholera,  are  all  preventable 
diseases,  carried  wholly  or  in  part 
by  insects.  The  enormous  sums 
of  money  spent  in  the  temporary 
control  of  these  diseases  might 
well  be  spent  in  a  more  effective 
manner,  i.  e.,  directed  toward  the 
root  of  the  evil — at  the  cause. 
"Eliminate  the  cause,  you  elim- 
inate the  effect."  This  is  the 
service  that  medical  entomology 
is  to  afford — its  aim  is  the  control 
of  disease  transmitting  insects. 
The  most  vulnerable  point  in  the 
life  history  of  the  insect  is  sought, 
and  the  most  effective  methods  of 
control  are  then  applied. 

METHODS  OF  DISEASE  TRANSMISSION. 

Broadly  speaking,  there  are  two 
methods  of  disease  transmission  in 
which  insects  are  concerned, 
namely,  a  direct  and  an  indirect 
method,  based  on  the  structure  of 
mouthparts.  The  direct  method  depends  upon  piercing  mouth  struc- 
tures (Fig.  1)  capable  of  penetrating  the  animal  skin  and  introducing 


Fig.  1. — Head  of  the  stable  fly,  Stomoxys 
calcitrans,  illustrating  the  type  of 
piercing  mouthparts  which  relate  to 
the  direct  transmission  of  pathogenic 
organisms.  The  sheath  or  labium 
encloses  slender,  piercing  bristles. 


Bulletin  215] 


THE   HOUSE   FLY   AND    HEALTH. 


515 


into  the  circulation  a  pathogenic  organism.  The  indirect  method  is 
based  on  the  accidental  accumulation  of  pathogenic  organisms  upon  foot 
or  mouth  structures  and  introducing  these  on  the  food  of  the  human 
being,  relating  mainly,  therefore,  to  intestinal  diseases,  such  as  typhoid 
fever,  Asiatic  cholera,  and  dysentery.  Other  than  this,  insects  may  act 
as  parasites,  both  external  (lice, 
etc.)  and  internal  (bot-flies,  etc.) 
causing  irritations  and  disease, 
or  they  may  produce  wounds  by 
the  introduction  of  a  specific 
poison  through  the  bite,  as  does 
the  bedbug,  the  kissing  bug,  and 
the  like. 

Two  common  insects  will  serve 
to  illustrate  the  two  principal 
methods,  namely,  the  stable  fly 
(Fig.  3)  on  the  one  hand— the 
direct  method ;  and  the  house  fly 
(Fig.  4)  on  the  other — the  indi- 
rect method.  The  former  pos- 
sesses mouthparts  which  are 
adapted  to  penetrate  the  skin 
(Fig.  1),  introducing  into  the 
blood  pathogenic  organisms 
which  attack  the  red  corpuscles! 
or  other  liquid  portions  of  the 
body,  such  as  the  cerebro-spinal 
fluid.  The  stable  fly  is  known  to 
transmit  a  Trypanosome  disease 
(Surra)  of  the  Philippine  Isl- 
ands (Laveran  et  Mesnil,  '04)  ;  a  closely  related  genus  the  Glossina  or 
Tsetse  fly  transmits  other  Trypanosome  diseases,  such  as  sleeping  sick- 
ness.    (Laveran  et  Mesnil,  '04.) 

The  second  type  (indirect)  is  represented  by  the  house  fly  (Fig.  4), 
an  important  transmitter  of  intestinal  diseases,  because  it  is  readily 
attracted  to  excrementous  matter,  vomit  and  sputum,  collecting  there 
the  "germs"  upon  its  mouthparts  (Fig.  2)  and  feet  and  then  carrying 
them  to  the  food  of  human  beings,  thus  readily  causing  infection.  The 
house  fly,  notwithstanding  public  opinion,  can  not  pierce  the  skin  since 
its  proboscis  is  quite  fleshy  and  not  equipped  with  piercing  bristles.  It 
is  the  stable  fly  which  inflicts  the  wound,  as  may  be  seen  by  a  careful 
examination  of  the  mouthparts  as  shown  in  the  illustration  (Fig.  1), 
but  because  of  the  mutual  resemblance  the  house  fly  is  blamed. 

Thus  we  see  that  the  usual  method  of  insect  classification,  that  of 


Fig.  2. — Head  of  the  house  fly,  Musca 
clomestica,  illustrating  the  type  of  suc- 
torial mouthparts  not  adapted  to 
piercing  the  human  skin  ;  but  because 
of  the  presence  of  numerous  bristles 
and  hairs  a  good  collector  of  filth  and 
germs  relating  to  the  indirect  trans- 
mission  of   disease. 


516 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 


Fig.  3. — The  stable  fly,  Stomoxys  calcitrans,  enlarged. 


biting  and  sucking  insects,  does  not  apply  in  this  work,  since  the  two 
forms  mentioned,  namely,  the  house  fly  and  the  stable  fly  are  both 
suctorial,  and,  indeed,  very  closely  related  systematically,  yet  they  relate 
very  differently  to  disease  transmission. 

It  is  wise  for  the  student  of  medical  entomology  to  note  the  distinction 

between  the  vege- 
table  pathogenic 
(disease  producing) 
organisms,  such  as 
the  bacteria,  and  the 
animal  pathogenic 
organisms,  such  as 
the  Protozoans,  since 
the  two  classes  vary 
considerably  in  their 
longevity  and  viru- 
lence when  outside 
the  human  body, 
and  behave  differently  within  the  bodies  of  different  insects,  e.  g., 
typhoid  fever  is  a  bacterial  disease,  the  causative  germs  of  which  outside 
the  body  are  present  in 
the  excrement  and  urine; 
malaria,  on  the  other 
hand,  is  a  Protozoan  dis- 
ease which  can  not  live 
outside  the  human  body, 
except  in  the  mosquito  of 
the  genus  Anopheles. 
Similar  contradistinctions 
might  be  made  between 
tuberculosis  and  African 
sleeping  sickness,  the 
pathogenic  bacterial  or- 
ganism of  the  former 
present  outside  the  body 
largely  in  the  sputum, 
and  the  protozoan  patho- 
genic organism  of  the 
latter  present  in  the  body 
of  the  Glossina  (Tsetse)  fly,  having  previously  been  sucked  up  with  the 
blood  by  this  sucking  fly.  Again,  bubonic  plague  is  a  bacterial  disease, 
while  Texas  fever  and  the  African  tick  fever  are  protozoan  types. 


Fig.  4. — The  house  fly,  Musca  domestica,  enlarged. 


Bulletin  215] 


THE    HOUSE   FLY    AND    HEALTH. 


51' 


WHAT  IS  THE  HOUSE  FLY? 

Properly  speaking,  only  one  species  of  fly  (Musca  domestica  Linn, 
Fig.  4)  is  rightly  called  the  house  fly,  though  there  are  several  species 
which  invade  the  house,  either  regularly  or  at  times.  A  brief  account  of 
these  latter  species  may  be 
useful  here  by  way  of  com- 
parison. The  blow  fly  or  blue 
bottle  fly  (Calliphora  vom- 
it oria,  Fig.  5)  is  the  large, 
noisy  fly  seen  frequently  on 
the  window  and  about  meat. 
This  is  typically  a  flesh  fly, 
depositing  its  eggs  on  the 
meat  in  the  pantry  or  else- 
where, finding  the  proper  food 
for  its  larvae  often  in  the  most 


Fig. 


5. — The  blow  fly  or  blue  bottle  fly, 
Calliphora  vomitoria,  enlarged. 


protected  situations.  The  female  often 
deposits  its  eggs  in  proximity  to  meat 
and  the  larvae  on  hatching  crawl  to  this 
food.  While  the  blow  fly  is  conspicuous 
it  is  not  as  plentiful  as  the  house  fly. 
and  is  not  as  liable  to  be  found  walking 
about  on  the  prepared  foods  of  man. 

Another  flesh  fly  conspicuous  because 
of  its  bright  metallic  green  color  is  the 
green  bottle  fly  (Lucilia  Ccesar,  Fig.  6). 
This  insect  rarely  comes  into  the  house, 
and  seldom  remains  long,  owing  to  its 
rapid  response  to  differences  in  light  in- 
tensities. (Herms,  '09  d  and  e.)  It  is 
typically  a  fly  of  the  out-of-doors,  and  a 

very  good  scavenger.     (Herms,  '07. ) 

The  stable  fly   (Stomoxys  calcitrans,  Fig.  3),  as  has  already  been 

mentioned,  is  often  confused  with  the  house  fly  because  of  its  close 


Fig.  6. — The  flesh  fly  or  green 
bottle  fly,  Lucilia  Caesar,  en- 
larged. 


518 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 


resemblance,  but  the  structure  of  the  mouthparts  will  serve  to  readily 

distinguish  the  two.    (Figs.  1  and  2.) 

Several  other  flies  are  commonly  found  indoors,  but  are  not  readily 

distinguished  from  the  common  house  fly;  only  careful  examination  of 

the  wing  venation  and  other  minute 
characters  can  serve  to  correctly  iden- 
tify the  species.  Several  species 
belonging  to  the  following  genera, 
Pollenia,  Morellia,  and  Muscina  belong 
to  the  same  family  as  the  house  fly, 
namely,  Muscidce,  while  others,  such 
a  s  Homalomyia  and  Anthomyia 
(Fig.  7),  belongs  to  another  family, 


Fig.  8. — Wing  of  the  house  fly,  Musca  do- 
mestical illustrating  the  typical  wing 
venation  of  the  Muscidae. 


Fig.  7. — Anthomya  fly  (enlarged), 
whose  larvae  are  known  as  root 
maggots.  This  fly  is  often  found 
indoors  and  closely  resembles  the 
house  fly. 

namely  Anthomyidce.  The  wing 
venation  of  the  two  families  is 
quite  characteristic,  as  illus- 
trated by  the  two  figures.  (Figs. 
8  and  9.)  The  cell,  marked  with 
an  x,  is  more  or  less  completely 
closed  in  the  Muscidce,  and  is 
open  in  the  Anthomyidce. 


Fig.  9. — Wing  of  the  Anthomya  fly,  Antho- 
myia radicum,  illustrating  the  typical 
wing  venation  of  the  Anthomyidae. 


LIFE  HISTORY  OR  DEVELOPMENT. 

By  life  history  is  meant  the  development  of  the  organism  from  the 
egg  to  the  adult.  The  house  fly  belongs  to  that  group  of  insects  which 
passes  through  a  complex  metamorphosis  unlike  that  of  the  grasshopper, 
for  example,  which  gradually  grows  up  to  the  adult  without  changing 
much  in  general  form.  The  house  fly,  on  the  other  hand,  passes  through 
several  stages,  each  unlike  the  other,  namely,  the  egg,  the  larva  (mag- 


Bulletin  215] 


THE   HOUSE   FLY    AND   HEALTH. 


519, 


got),  the  pupa  (resting  stage),  and  the  imago  or  full  grown  winged 
insect.     (Fig.  10.) 

From  75  to  125  eggs  are  deposited  singly  in  one  mass,  and  there  are 
usually  several  (2  to  4)  such  layings.  Excrementous  material,  especially 
of  the  horse,  is  the  favorite  place  upon  which  the  eggs  are  deposited. 
Other  suitable  situations  are  kitchen  refuse,  unused  brewer 's  grain,  and 
other  decaying  vegetable  matter.  Where  the  city  garbage  is  carefully 
disposed  of  with  only  ordinary  attention  to  horse  manure  it  seems  quite 
safe  to  say  that  ninety-five  per  cent  of  the  house  flies  are  bred  in  the 
latter  situation.  (An  effort  made  to  breed  these  flies  in  the  laboratory 
in  cow  manures  proved  unsuccessful,  but  adults  were  reared  from  full 
grown  larvae  and  pupae  collected  in  and  near  the  manure  pile  from  the 
dairy,  showing  that  the  house  fly  may  breed  in  this  material,  though 


Fig.  10. — Illustrating  the  life  history  of  the  house  fly:  a  egg  stage;  b  larval 
stage  or  maggot,  full  grown  ;  c  resting  stage  or  pupa  ;  d  the  imago  or  adult. 

probably  only  to  a  limited  extent.)  The  eggs  hatch  in  from  twelve  to 
twenty-four  hours  and  the  newly  hatched  larvae  begin  feeding  at  once. 
To  gain  an  estimate  of  the  number  of  larvae  developing  in  an  average 
horse  manure  pile,  samples  were  taken  from  such  a  pile  after  an  expo- 
sure of  four  days  with  the  following  results:  First  sample  (4  lbs.)  con- 
tained 6,873  larvae;  second  sample  (4  lbs.),  1,142;  third  sample  (4  lbs.), 
1,585;  fourth  sample  (3  lbs.),  682;  total,  10,282  larvae  in  15  pounds. 
(Herms,  '09.)  All  these  larvae  were  quite  or  nearly  full  grown.  This 
gives  an  average  of  685  larvae  per  pound.  The  weight  of  the  entire  pile 
was  estimated  at  not  less  than  1,000  pounds,  of  which  certainly  two 
thirds  was  infested.  A  little  arithmetic  gives  us  the  astonishing  estimate 
of  455,525  larvae  (685  x  665),  or  in  round  numbers,  450,000.  This  par- 
ticular manure  pile  (not  from  a  livery  stable,  either),  was  only  one  of 
many  known  to  exist  in  various  parts  of  the  city.    No  wonder  flies  fairly 


520 


UNIVERSITY   OF    CALIFORNIA EXPERIMENT    STATION. 


swarm  in  the  vicinity  of  these  choice  ornaments!  Five  samples  of  an 
ounce  and  a  half  of  manure  each  furnished  the  following  numbers,  viz. : 
(1)  58  larva?,  (2)  64,  (3)  70,  (4)  228,  (5)  49.  Total,  469  larva?  to  seven 
and  one  half  ounces,  an  average  of  nearly  one  thousand  per  pound. 

The  larval  stage  is  the  growing  period  of  the  fly  and  the  size  of  the 
adult  will  depend  entirely  upon  the.  size  that  the  larva  attains.     An 

underfed  larva  will  result  in  an 
undersized  adult,  which  fact  is  well 
illustrated  by  Fig.  11,  based  on 
experiments  tried  on  the  flesh  fly, 
Lucilia  Ccesar.  (Herms,  '07.)  This 
growing  stage  requires  from  four 
to  six  days,  after  which  the  maggots 
often  crawl  away  from  their  breed- 
ing place,  many  of  them  burrowing 
into  the  loose  ground  just  under- 
neath the  manure  pile,  or  crawling 
under  boards  or  stones,  or  into  dry 
manure  collected  under  platforms 
and  the  like.  (One  and  three 
fourths  pounds  of  dry  manure, 
taken  from  a  situation  last  men- 
tioned, contained  2,561  pupaa.)  The 
larvae  often  pass  three  or  four  days 
in  the  prepupal  or  migrated  stage 
before  actually  pupating;  but  in  a 
given  set  of  individuals  under  simi- 
lar conditions  the  various  stages  are 
remarkably  similar  in  duration, 
when  one  pupates  the  rest  will  cer- 
tainly follow  in  short  order,  and 
when  one  emerges  as  an  adult 
others  quickly  appear.  The  aver- 
age time  required  for  development 


1. 


2. 


3. 


6. 


Larva  overfed, 
pupation  re- 
tarded. 


Optimum, 
60-72  hours. 


60  hours. 


54  hours. 


4  8  hours. 


42  hours. 


36  hours. 


Fig 


derL^ng^ela'rva'hLtn^e^L^r  is  differently  estimated  by  various 


observers,  inasmuch  as  temperature 


the  adult  fly  (Lticilia  Caesar).  Over- 
feeding,   if    it    does    not    result    fatally, 

fhfo^um^m'S'mVy'^be0^^  %°&  greatly  influences  the  time  required. 

uppermost  individual,  which  is  the  same 
size  as  the  next  lower  individual  or 
Optimum.  Each  of  the  next  lower  in- 
dividuals is  the  result  of  decreasing  the 
time  of  feeding  by  six  hours.  These 
results  are  based  on  a  large  number  of 
individuals  in  each  case. 


Packard  (74)  gives  the  time  at 
from  ten  to  fourteen  days,  Howard 
('06)  at  Washington,  D.  C,  as  ten 
days.  In  Berkeley,  where  the 
weather  is  uniformly  cooler  (rarely  above  80°  and  a  mean  of  48°  during 
the  winter  months)  the  life  cycle  is  completed  usually  in  from  fourteen 
to  eighteen  days,  less  often  in  twelve  days.     Prolonged  cool  weather  or 


Bulletin  215] 


THE   HOUSE   FLY    AND    HEALTH. 


521 


artificially  cooled  environment  results  in  greater  retardation.  Even 
allowing  for  such  retardation,  the  number  of  generations  produced 
during  the  summer  is  quite  large  and  in  California  (Berkeley)  I  have 
seen  house  flies  emerging  from  their  breeding  places  during  every  month 
of  the  winter  season.  This  latter  fact  lends  even  greater  importance  to 
a  house  fly  campaign.  In  early  March  a  veritable  pest  of  flies  was 
encountered  while  on  a  trip  through  the  Imperial  Valley  (California). 
When  the  fly  emerges  from  the  pupa  case  with  fully  developed  wings, 
it  is  as  large  as  it  ever  will  be,  except  in  expansion  of  tissue  and  addition 
in  weight,  due  to  stomach  contents  or  development  of  eggs  in  the  female. 
This  explains  why  no  young  house  flies  are  seen  (young  in  the  sense  of 
being  small).  The  little  flies  upon  the  windows  are  not  "baby"  flies, 
but  belong  to  another  species,  also  adult.  One  can  easily  influence  the 
size  of  a  fly  by  underfeeding  it  in  the  larval  stage,  as  illustrated  in 
Fig.  10  (see  Herms,  '07).  The  question  has  been  asked,  "Why  are  all 
house  flies  so  nearly  of  one  size?"  This  is  not  altogether  true.  There 
are  some  undersized  house  flies,  but  the  greater  majority  of  the  larvae 
or  maggots  find  ample  food  for  optimum  development.  Furthermore, 
experiments  show  that  the  house  fly  is  not  as  plastic  in  respect  to  food 
conditions  as  the  flesh  fly,  for  instance :  in  other  words,  larvae  which  are 
underfed  perish  easily. 

In  order  to  determine  the  distribution  of  the  sexes,  observations  were 
made  under  two  different  conditions,  viz.,  first,  six  sweepings  with  an 
insect  net  were  made  over  a  horse  manure  pile  on  which  many  flies  had 
gathered  (the  results  are  shown  in  Table  I)  ;  second,  all  but  half  a  dozen 
flies  were  collected  in  one  house,  giving  a  fairly  representative  lot  for 
indoors,  even  under  screened  conditions.     (See  Table  II.) 

TABLE   I. 
Showing  results  with  regard  to  sexes  and  species  in  six  sweepings  from  a  horse  manure 

pile  on  May  18  and  19,  1909. 


First. 

Second. 

Third. 

Fourth. 

Fifth. 

Sixth. 

Total. 

M 

F 

M 

F 

M 

F 

M  '    F 

M 

F 

M 

F 

M 

F 

House      fly       ( Musca 
domestica)    

Muscina    stabulans 

Blow   fly    (Calliphora 
vo'mitoria)     

Lucilia  Cwsar 

Other  species* 

7 
2 

2 
0 

1 

153 
6 

2 
1 
4 

4 
0 

0 
0 
0 

81 

7 

1 
1 

4 

3 

0 

1 
0 
2 

64 
5 

0 

1 
1 

9 
2 

0 
0 
4 

77 
5 

0 
1 
2 

4 
3 

0 
0 
4 

210 
10 

0 
0 
2 

5 

1 

1 
0 
2 

112 
4 

0 
0 
0 

32 

8 

3 

0 

13 

697 
37 

3 
4 

13 

Totals 

12 

166 

4 

94 

6 

71 

15 

85 

11 

222 

9 

116 

56 

754 

♦Including  Anthomyids  and  Scatophagids,  but  excluding  many  tiny  Diptera,  prob- 
ably Sepsis. 


522  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT   STATION. 

TABLE  II. 
Showing  number  of  individuals  collected  in  a  screened  dwelling  June  1, 


M 


House  fly,  Musca  domestica. 

Muscina  sp.   

Homalomyia    sp.    

Calliphora    

Totals   


95 


116 
1 
0 
2 


119 


Explanation  and  comparison  of  Tables  I  and  II. — These  two  tables 
give  us  some  information  as  to  the  relative  abundance  of  the  house  fly, 
and  the  distribution  of  the  sexes.  Table  I  shows  clearly  that  of  those 
flies  which  frequent  both  the  manure  pile  and  the  home,  the  house  flies 
compose  90  per  cent,  and  that  of  the  total  collected,  over  95  per  cent 
(95.4  per  cent)  were  females.  Thus,  it  is  clear  that  it  is  the  " instinct' ' 
to  oviposit  (to  lay  eggs)  that  has  mainly  attracted  these  insects  to  this 
situation.  In  fact,  fresher  parts  of  the  manure  pile  are  often  literally 
white  with  house  fly  eggs  in  countless  numbers.  Observations  made  in 
the  near  vicinity  of  the  manure  pile  proved  that  certainly  the  same  per- 
centage (over  95  per  cent)  of  the  flies  clinging  to  the  walls  of  the  stable, 
boxes,  and  so  on,  were  males. 

Of  the  total  number  of  house  flies  (202)  collected  indoors  (June,  '09), 
representing  all  but  perhaps  six  of  the  total  number  in  that  particular 
house,  57  per  cent  were  females,  showing  nearly  equal  distribution  for 
the  sexes.  This  would,  it  seems,  indicate  that  the  sexes  of  this  insect  are 
equally  attracted  to  the  house  by  odors  issuing  therefrom.  Another 
interesting  point  is  that  of  the  total  number  of  flies  thus  collected 
indoors  (214),  94.4  per  cent  were  the  common  house  fly.  This  estimate 
can  not,  of  course,  be  taken  as  a  standard.  The  number  is  entirely  too 
small,  but  it  does  come  very  near  the  percentage  determined  by  Dr.  L.  0. 
Howard  (Howard,  '00),  who  "made  collections  in  the  dining-rooms  in 
different  parts  of  this  country,  and  out  of  a  total  of  23,087  flies,  22,808 
were  Musca  domestica,  that  is  98  per  cent  of  the  whole  number  cap- 
tured." 

That  the  sexes  in  the  housefly  are  normally  about  equal  in  number  is 
apparent,  inasmuch  as  of  a  total  of  264  pupse  collected  indiscriminately 
and  allowed  to  emerge  in  the  laboratory,  129  were  males  and  135  were 
females.  The  author  has,  however,  made  observations  on  the  flesh  flies, 
Lucilia  Ccesar,  and  Calliphora  vomitoria,  which  indicate  that  the  factor 
of  underfeeding  must  be  considered  in  this  connection.  From  a  large 
amount  of  unpublished  data,  it  seems  evident  that  underfeeding  results 


Bulletin  215] 


THE    HOUSE   FLY   AND    HEALTH. 


523 


in  the  emergence  of  a  greater  percentage  of  males ;  this  does  not  mean, 
however,  that  sex  is  influenced  by  feeding,  it  only  means  that  cutting 
short  on  food  supply  destroys  the  larval  females  first.  Feeding  experi- 
ments, not  yet  complete,  on  the  house  fly  indicate  that  the  same  holds 
true  here,  but  also  that  this  insect  is  not  so  plastic  as  the  flesh  fly,  hence 
does  not  vary  so  greatly  in  size  and  dies  more  easily  when  underfed. 

Anatomical  considerations  are  here  omitted,  inasmuch  as  that  phase  of 
the  subject  is  admirably  treated  in  a  work  by  Hewitt  ( '07). 

RELATION  TO  DISEASE  TRANSMISSION. 

We  should  be  familiar  with  the  actual  method  of  disease  transmission 
by  the  house  fly.  Some  insects  act  as  intermediate  host  for  pathogenic 
organisms,  which  latter  can  not  exist  sexually  and  be  transmitted  with- 
out the  insect,  e.  g.,  the  malarial  fever  parasite  (Plasmodium  malarice 
and  other  species),  which  passes  part  of  its  life  history  in  the  body  of 
the  Anopheles  mosquito.     The  house  fly,  as  far  as  known,  is  not  an 


Fig.  12. — Foot  of  the  house  fly  greatly  enlarged.     Note  the  many  fine 
hairs  with  which  the  foot-pads  are  provided. 

intermediate  host  necessary  to  the  life  history  of  a  pathogenic  organism, 
but  is  by  accident  of  habit  and  structure  one  of  the  most  important  and 
dangerous  of  disease  transmitting  insects.  In  habit  the  house  fly  is 
revoltingly  filthy,  feeding  indiscriminately  on  excrement  of  all  kinds,  on 
vomit  and  sputum,  and  is,  on  the  other  hand,  equally  attracted  to  the 
daintiest  foods  of  man,  and  will,  if  unhindered,  pass  back  and  forth 
between  the  two  extremes.  The  house  fly's  proboscis  (Fig.  2)  is  pro- 
vided with  a  profusion  of  fine  hairs  which  serve  as  collectors  of  germs 
and  filth;  the  foot  of  the  fly  when  examined  under  the  microscope 


524  UNIVERSITY   OF    CALIFORNIA EXPERIMENT    STATION. 

presents  an  astonishing  complexity  of  structure,  illustrated  in  Fig.  12. 
Each  of  the  six  feet  is  equally  fitted  with  bristly  structures  and  pads, 
which  secrete  a  sticky  material,  adding  thus  to  their  collecting  powers. 
This  structural  condition,  added  to  the  natural  vile  habits  of  the  house 
fly.  completes  its  requirements  as  a  transmitter  of  infectious  diseases. 

This  creature  has  long  been  known  to  contaminate  food,  but  has, 
nevertheless,  been  regarded  as  a  scavenger,  and  thus  as  a  real  servant 
of  man,  but  if  there  remains  any  doubt  in  the  mind  of  the  reader,  after 
reading  what  follows,  as  to  the  necessity  of  getting  rid  of  this  wolf  in 
sheep 's  clothing,  let  him  take  the  time  to  make  a  few  careful  observations 
for  himself. 

Circumstantial  evidence  against  the  house  fly  as  a  transmitter  of  such 
infectious  diseases  as  typhoid  fever,  tuberculosis,  dysenteries,  and 
cholera  is  complete  as  summed  up  thus :  First,  it  possesses  the  best  pos- 
sible structures  for  the  conveyance  of  " germs"  and  filth;  second,  it 
possesses  the  habit  of  feeding  on  excrementous  matter  of  all  kinds,  vomit 
and  sputum;  third,  the  causative  organisms  ("germs")  of  the  above 
named  diseases  are  present  in  the  matter  mentioned  in  the  second  clause ; 
fourth,  the  house  fly  is  the  principal  fly  found  in  dwellings,  alighting 
upon  the  prepared  food  of  man,  or  on  food  products  in  grocery  stores, 
fruit  stands  and  meat  markets. 

Experimental  evidence  that  the  house  fly  actually  does  carry  bacteria 
upon  its  mouthparts  and  feet  or  in  its  intestinal  tract  is  not  wanting. 
To  illustrate,  the  following  simple  experiment  may  be  cited. 

In  order  to  show  that  the  house  fly  (Musca  domestica)  can  carry 
"germ"  of  a  known  kind,  a  partly  sterilized  fly  was  placed  in  a  test 
tube  containing  a  culture  of  Micrococcus  aureus.  After  walking  about 
in  this  tube  and  becoming  contaminated  with  the  Micrococci,  the  fly 
was  transferred  to  a  sterile  agar-agar  plate  upon  which  it  was  allowed 
to  crawl  about  for  three  minutes.  The  plate  was  then  incubated  for 
twenty-four  hours,  after  which  it  was  examined  and  photographed,  as 
shown  in  Fig.  13. 

The  photograph  shows  the  trail  of  the  fly  as  it  had  walked  about. 
Every  place  that  the  foot  touched  is  plainly  marked  by  a  vigorous 
bacterial  growth.  That  the  fly  can  not  easily  get  rid  of  all  the  bacteria 
on  its  feet  is  also  illustrated  by  this  photograph,  inasmuch  as  three 
minutes  spent  crawling  about  on  the  agar  plate  did  not  apparently 
lessen  the  growth-vigor  of  bacteria  deposited,  and  a  second  plate  of 
agar-agar  contaminated  by  the  same  fly  immediately  after  exposure  of 
the  first  plate  gave  equally  striking  results.  The  same  experiment  was 
performed,  using  the  Bacillus  prodigeosus  with  even  more  pronounced 
results,  as  shown  in  Fig.  14.  These  experiments  were  repeated  several 
times  with  like  effect. 


Bulletin  215] 


THE    HOUSE    FLY   AND    HEALTH. 


525 


A  second  series  of  experiments  was  carried  on  as  follows :  During  the 
midde  of  May  (1909)  house  flies  were  captured  in  various  parts  of 
Berkeley,  placed  at  once  in  sterilized  vials,  and  in  the  laboratory  placed 
under  bell  jars  with  agar-agar  plates,  all  under  sterilized  conditions. 
After  the  flies  had  crawled  about  on  the  culture  media,  the  latter  was 
incubated  for  twenty-four  hours.  In  every  case,  but  one,  a  strong 
growth  of  bacteria  appeared.  This  one  was  incubated  longer  and  after 
forty  hours  four  centers  of  infection  appeared.  This  fly  had  been  taken 
on  a  sunny  wall  on  one  of  the  main  streets,  and  having  been  under 


Fig.  13. — Cultures  of  Micrococcus  aureus  transferred  bv  a  house  fly 
to  a  sterile  agar-agar  plate  upon  which  it  was  allowed  to  crawl  for 
three  minutes.      Incubation  period   24   hours. 


observation  in  this  position  for  a  long  time  (as  reported  by  the  assistant) 
it  was  first  supposed  that  the  action  of  the  sunlight  had  sterilized  it. 
This  series  of  experiments  included  flies  taken  from  a  number  of  situa- 
tions, namely,  principal  thoroughfares,  sunny  walls,  street  corners, 
manure  piles,  and  the  dining-room.  Without  exception  these  flies  were 
laden  with  bacteria,  and  in  all  cases  the  greatest  care  was  exercised  not 
to  introduce  any  accidental  infection  on  to  the  culture  plates. 

2— Bul.  215 


526 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


Probably  the  most  accurate  study  of  these  factors  was  carried  on  by 
Est  en  and  Mason  (Esten  and  Mason,  '08)  on  the  "  Sources  of  Bacteria 


Fig.  14. — Cultures  of  Bacillus  prodigeosus  transferred  by  a  house 
fly  to  a  sterile  agar-agar  plate  upon  which  it  was  allowed  to 
crawl    for    only    a    few   moments.      Incubation    period    24    hours. 

in  Milk, ' '  and  certainly  most  striking  facts  were  revealed.  The  follow- 
ing table  and  attached  remarks  are  taken  from  that  publication,  and 
need  no  further  comments  or  explanations : 


Bulletin  2151 


THE  HOUSE  FLY  AND  HEALTH. 


527 


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528  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

"From  the  above  table  the  bacterial  population  of  414  flies  is  pretty 
well  represented.  The  domestic  fly  is  passing  from  a  disgusting  nuisance 
and  troublesome  pest  to  a  reputation  of  being  a  dangerous  enemy  to 
human  health.  #  *  *  The  numbers  of  bacteria  on  a  single  fly  may 
range  all  the  way  from  550  to  6,600,000.  Early  in  the  fly  season  the 
numbers  of  bacteria  on  flies  are  comparatively  very  small,  while  later 
the  numbers  are  comparatively  very  large.  The  place  where  flies  live 
also  determines  largely  the  numbers  that  they  carry.  The  average  for 
414  flies  was  about  one  and  one  fourth  millions  bacteria  on  each.  It 
hardly  seems  possible  for  so  small  a  bit  of  life  to  carry  so  large  a  number 
of  organisms.  *  *  *  The  objectionable  class,  coliaerogenes  type,  was 
two  and  one  half  times  as  abundant  as  the  favorable  acid  type. ' ' 

TYPHOID  FEVER. 

The  causative  organism  {Bacillus  typhosus)  of  typhoid  fever  belongs 
to  a  group  known  as  the  typhoid-dysentery  group,  and  is  found  outside 
the  human  body  "only  in  those  situations  where  it  could  be  more  or  less 
directly  traced  to  an  origin  in  the  discharge  of  a  typhoid  patient  or 
convalescent."  Jordan  ('08)  and  others  have  shown  that  the  life  of 
this  germ  in  the  water  of  flowing  streams  is  of  comparatively  short 
duration,  and  that  multiplication  does  not  ordinarily  take  place  in 
water ;  indeed,  a  steady  decline  in  numbers  goes  on.  Infection  caused 
by  transmission  through  the  air  is  exceedingly  rare  according  to  these 
authors,  but  soil  on  the  contrary  may  become  contaminated  through 
buried  human  excrement,  or  otherwise,  and  continue  to  be  a  source  of 
infection  for  a  much  longer  time  than  water.  Notwithstanding  these 
facts,  the  majority  of  typhoid  fever  epidemics  are  traceable  to-  water 
infection,  but  indicate  fresh  contamination  and  not  one  of  long  standing. 

Within  the  human  body  the  typhoid  bacilli  are  found  mainly  in  the 
intestine,  and  also  in  the  urinary  bladder,  and  in  the  majority  of  cases 
are  present  in  the  blood  stream  (Jordan,  '08).  The  bacilli  are  dis- 
charged from  the  body  with  the  faeces  and  the  urine;  and  are  often 
present  in  such  discharges  for  a  period  of  ten  weeks,  and  in  chronic 
carriers  for  at  least  two  years  after  recovery.  An  added  source  of 
danger  is  the  presence  of  virulent  bacilli  in  light  cases  of  typhoid  fever, 
known  as  the  ' '  walking  typhoid, ' '  where  little  or  no  precaution  is  exer- 
cised, but  which  may  result  in  the  severest  types  in  others  infected  from 
such  individuals. 

These  facts  aid  in  interpreting  the  role  of  flies  in  typhoid  transmis- 
sion. Flies  are  attracted  by  excrementous  matter,  as  has  already  been 
stated,  and  subsist  entirely  upon  liquid  foods,  thus  contaminating  their 
mouthparts  and  feet,  which,  if  the  faeces  contain  virulent  bacilli,  must 
now  fairly  reek  with  filth  and  disease.  Thus  equipped  the  fly  next 
makes  its  way  to  the  dining-room  of  man  or  to  grocery  stores,  fruit 
stands,  etc.,  depositing  there  through  the  digecta  or  by  means  of  the 


Bulletin  215]  The  HOUSE  FLY  AND  HEALTH.  529 

soiled  proboscis  and  feet  the  typhoid  bacillus  upon  the  food  which  is 
eaten  by  the  human  family.  Thus,  during  the  Spanish- American  war 
(Veeder,  '98),  flies  with  lime-covered  feet  were  actually  seen  crawling 
over  the  food  of  the  soldiers.  The  whitened  feet  were  the  result  of  lime 
and  filth  collected  from  the  camp  latrines.  The  depredations  of  typhoid 
fever  at  that  time  really  mark  the  beginning  of  the  widespread  campaign 
against  the  house  fly. 

Jordan  ( '08)  states,  "not  only  may  bacilli  stick  to  the  legs  and  wings 
of  these  insects,  but  if  swallowed  they  may  survive  the  passage  of  the 
alimentary  tract.  Typhoid  bacilli  have  been  isolated  from  house  flies 
captured  in  houses  in  Chicago,  in  the  neighborhood  of  badly  kept  privy 
vaults  used  by  typhoid  patients,  and  it  has  been  shown  experimentally 
that  living  bacilli  may  remain  in  or  upon  the  body  of  flies  for  as  long  as 
twenty-three  days  after  infection." 

The  writer's  attention  was  called  to  a  series  of  sporadic  cases  of 
typhoid  fever,  plausibly  traceable  to  flies,  thus:  a  certain  carpenter 
recently  recovered  from  typhoid  fever,  resumed  his  work,  making  use 
of  a  box  privy,  such  as  is  often  used  in  connection  with  buildings  under 
construction.  In  the  immediate  vicinity  there  lived  a  milk  dealer,  who, 
after  washing  his  cans,  placed  them  on  the  roof  of  a  shed  to  drain  and 
dry.  Flies  are  fond  of  milk,  even  highly  diluted  with  water.  The  cases 
of  typhoid  fever  in  question  were,  on  investigation,  found  to  be  cus- 
tomers of  this  particular  dealer.  The  argument  is  good  and  reasonably 
conclusive. 

The  pollution  of  the  waters  of  New  York  harbor  has  been  made  the 
object  of  special  study  by  Jackson  ('09).  In  his  report  to  the  "Mer- 
chants '  Association ' '  of  New  York,  he  shows  that  the  sewage  is  not 
carried  away  by  the  tides,  and  "that  at  many  points  sewer  outfalls  have 
not  been  carried  below  the  low-water  mark,  in  consequence  of  which  the 
solid  matters  from  the  sewers  have  been  exposed  on  the  shores. ' '  These 
deposits  were  found  to  be  covered  with  flies,  thus  affording  ample  oppor- 
tunity for  the  transmission  of  typhoid.  It  was,  furthermore,  found  that 
the  greater  number  of  typhoid  cases  were  found  near  the  water  front, 
and  if  the  curve  showing  the  prevalence  of  cases  was  set  back  two  months 
it  coincided  with  the  curve  showing  the  prevalence  of  house  flies.  The 
period  of  two  months  represents  the  time  of  incubation.  The  fly  curve, 
of  course,  also  coincides  with  the  temperature  curve,  but  hot  weather 
alone  can  not  account  for  the  dissemination  of  the  typhoid  bacillus. 

DYSENTERY. 

There  are  at  least  two  varieties  of  dysentery ;  one  of  which  is  caused 
by  a  bacillar  organism,  as  in  typhoid  fever,  and  is  known  as  Bacillus 
dysenterice  and  the  other  variety  is  caused  by  a  protozoan  organism 
(entomoeba),  known  as  Entomeba  histolytica.2    The  former  variety  is 

2 Jordan  loc.  cit.  p.  430. 


530  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

known  to  be  the  prevalent  type  in  temperate  climates,  while  the  latter 
is  commonest  in  the  tropics.  The  causative  organisms  of  both  are  found 
in  great  numbers  in  the  stools  of  patients.  The  mode  of  infection  is 
without  doubt  the  same  as  mentioned  in  typhoid  fever,  and  in  which 
the  house  fly  also  certainly  plays  an  important  role. 

SUMMER  DIARRHEA  IN  INFANTS. 

A  type  of  Bacillus  dy sentence3  is  present  in  the  stool  of  infants 
suffering  from  summer  diarrhea.  Thousands  of  infants  die  every  sum- 
mer from  this  complaint.  It  is  well  known  that  flies  are  strongly 
attracted  by  the  stools  from  infants  thus  affected,  and  in  the  second 
place,  consecutive  to  the  argument,  little  children  are  greatly  molested 
by  flies,  inasmuch  as  they  often  have  milk  vomits  on  their  little  dresses 
and  around  the  mouth  attractive  to  flies,  and  are  quite  helpless.  How 
often  does  one  see  the  house  fly  lingering  menacingly  around  the  mouth 
of  the  helpless  infant.  Keep  the  flies  away  from  the  babies  by  the  use 
of  screens  and  nettings,  and  thus  avoid  in  great  measure  the  most 
dreaded  disease  of  the  infant.  Do  not  permit  the  flies  to  crawl  around 
on  the  child's  face  and  hands. 

TUBERCULOSIS. 

Tuberculosis  is  caused  by  a  specific  organism,  Bacillus  tuberculosis, 
which  may  invade  practically  every  organ  and  tissue  of  the  human  body. 
The  lungs  are  commonly  the  seat  of  lesions,  as  are  the  intestines,  the 
liver  and  the  urogenital  organs.  The  causative  germs  find  their  way  out- 
side the  body  through  the  sputum,  the  fseces,  and  the  urine,  depending 
on  the  location  of  the  lesions. 

In  the  study  of  transmission  the  considerable  powers  of  resistance 
which  these  bacilli  possess  are  highly  important.  Dried  phthisical 
sputum  has  been  found  to  contain  still  virulent  bacilli  (or  their  spores) 
after  two  months.  Sputum  has  been  found  to  contain  living  tubercle 
bacilli  even  after  being  allowed  to  putrefy  for  several  weeks.  (Muir  and 
Ritchie,  '07).  Sunlight  is  ordinarily  a  good  disinfectant,  killing  bac- 
teria very  quickly  when  properly  exposed,  but  it  requires,  as  Jordan 
states,  from  twenty  to  twenty-four  hours  or  even  longer  to  kill  the 
tubercle  bacillus  when  present  in  sputum. 

These  facts  are  most  important  when,  coupled  with  them,  it  is  recog- 
nized that  recent  investigations  prove  that  infection  is  possible  through 
the  intestinal  tract,  by  way  of  infected  food  introduced  into  the  mouth. 
Thus,  flies  are  known  to  feed  readily  on  sputum  of  tuberculous  indi- 
viduals, and,  as  in  typhoid  fever,  may  deposit  the  bacilli  upon  human 
food. 

"Von  Behring  maintains  that  the  vast  majority  of  all  cases  of  lung 
tuberculosis  are  of  intestinal  origin,  and  there  is  no  doubt  that  pulmo- 

Jordan   pp.    284-285. 


Bulletin  215]  THE  HOUSE  FLY  AND  HEALTH.  531 

nary   tuberculosis   can   originate   from   swallowing   tubercle   bacilli." 
(Jordan,  '08.) 

It  has  been  proved  beyond  doubt  that  the  house  fly  can  carry  with  it 
in  its  intestinal  tract  the  bacillus  tuberculosis.  "The  belief  that  flies 
(Musca  domestica)  which  have  fed  on  tubercular  sputum  may  serve  as 
carriers  and  disseminators  of  the  tubercle  bacillus  first  led  Spillman 
and  Haushalter  (1887)  to  investigate  the  problem.  They  examined  such 
flies  and  also  their  excreta  deposited  on  the  walls  and  windows  of  a 
hospital  ward,  and  were  able  to  determine  microscopically  the  presence 
of  large  numbers  of  tubercle  bacilli,  both  in  the  intestines  of  the  flies  and 
their  excrement."  (Nuttall,  '99.)  Howard  ('09)  in  a  bulletin  already 
cited,  quotes  the  following  from  "a  paper  by  Dr.  Frederick  T.  Lord 
('04)  of  Boston": 

1.  Flies  may  ingest  tubercular  sputum  and  excrete  tubercle  bacilli,  the  virulence 
of  which  may  last  for  at  least  fifteen  days. 

2.  The  danger  of  human  infection  from  tubercular  flyspecks  is  by  the  ingestion  of 
the  specks  on  food.  Spontaneous  liberation  of  tubercle  bacilli  from  fly  specks  is 
unlikely.     If  mechanically  disturbed,  infection  of  the  surrounding  air  may  occur. 

As  a  corollary  to  these  conclusions  it  is  suggested  that — 

3.  Tubercular  material  (sputum,  pus  from  discharging  sinuses,  faecal  matter  from 
patients  with  intestinal  tuberculosis,  etc.)  should  be  carefully  protected  from  flies, 
lest  they  act  as  disseminators  of  the  tubercle  bacilli. 

4.  During  the  fly  season  greater  attention  should  be  paid  to  the  screening  of  rooms 
and  hospital  wards  containing  patients  with  tuberculosis,  and  laboratories  where 
tubercular  material  is  examined. 

5.  As  these  precautions  would  not  eliminate  fly  infection  by  patients  at  large, 
foodstuffs  should  be  protected  from  flies  which  may  already  have  ingested  tubercular 
material. 

The  investigations  by  Dr.  Ch.  Andre,  of  the  University  of  Lyons,  were 
reported  upon  at  the  Anti-Tuberculosis  Congress  at  Washington,  1908, 
viz. : 

The  results  of  this  investigation  are  as  follows  : 

Flies  are  active  agents  in  the  dissemination  of  Koch's  bacillus  because  they  are 
constantly  going  back  and  forth  between  contagious  sputa  and  faeces,  and  foodstuffs, 
especially  meat,  fruit,  milk,  etc.,  which  they  pollute  by  contact  with  their  feet,  and 
especially  with  their  excretions. 

The  experimental  researches  of  the  author  show  the  following : 

1.  Flies  caught  in  the  open  air  do  not  contain  any  acid-fast  bacilli  that  could  be 
mistaken  for  the  bacillus  of  Koch. 

2.  Flies  that  have  been  fed  on  sputum  evacuate  considerable  quantities  of  bacilli 
in  their  excretions.  The  bacilli  appear  six  hours  after  ingestion  of  the  sputum,  and 
some  may  be  found  as  long  as  five  days  later.  These  flies,  therefore,  have  plenty  of 
time  to  carry  these  bacilli  to  a  great  distance,  and  to  contaminate  food  in  houses 
apparently  protected  from  contagion,  because  not  inhabited  by  a  consumptive. 

3.  Food  polluted  by  flies  that  have  fed  on  sputa  contains  infective  bacilli  and 
produces  tuberculosis  in  the  guinea  pigs. 

4.  Flies  readily  absorb  bacilli  contained  in  dry  dust. 

5.  Flies  caught  at  random  in  a  hospital  ward  produce  tuberculosis  in  the  guinea 
pig. 

Practical  Conclusions. — The  sputa  and  faeces  of  tuberculous  subjects  must  be 
disinfected ;  flies  should  be  destroyed  as  completely  as  possible ;  foodstuffs  should  be 
protected  by  means  of  covers  made  of  wire  gauze. 


532  UNIVERSITY   OF    CALIFORNIA — EXPERIMENT    STATION. 

ASIATIC  CHOLERA. 

Asiatic  cholera,  as  the  name  indicates,  is  endemic  in  Asia  (India),  but 
has  spread  over  the  larger  part  of  the  world  during  the  past  century, 
appearing  as  epidemic  in  Africa  and  Europe.  The  disease  relates  to  the 
intestinal  tract,  and  is  of  bacterial  origin  (Spirillum  cholerce).  The 
cholera  spirillum  leaves  the  body  with  the  stools,  and  infection  is  trace- 
able to  this  source.  "Upon  the  surface  of  vegetables  and  fruits  kept  in 
a  cool  moist  place,  experiments  have  shown  that  the  spirillum  may  retain 
its  vitality  for  from  four  to  seven  days."     (Jordan,  '08.) 

Cholera  was  one  of  the  first  diseases  with  which  flies  were  associated 
as  transmitters,  and  the  experimental  evidence  that  has  since  been  pro- 
duced is  no  less  complete  than  in  typhoid  fever.  Without  advancing  the 
evidence  as  presented  by  Nuttall  ( '99) ,  the  following  statement  made  by 
that  eminent  authority  will  serve  the  purpose,  viz. :  ' '  The  body  of 
evidence  here  presented  as  to  the  role  of  flies  in  the  diffusion  of  cholera 
is,  I  believe,  absolutely  convincing. ' ' 

OTHER  DISEASES  TRANSMITTED. 

The  pus  forming  or  suppurative  bacteria  (Staphylococci)  are  largely 
carried  by  the  house  fly.  Thus,  the  suppurative  eye  disease  of  Egypt  is 
said  to  be  transmitted  by  the  common  house  fly  (Nuttall,  '99),  while 
Florida  sore  eye,  or  "pink  eye,"  is  evidently  directly  traceable  to  a 
little  fly  having  mouthparts  similar  to  the  house  fly  known  as  the 
Hippelatesfty  (Nuttall,  '99). 

Under  certain  conditions  it  is  very  probable  also  that  the  house  fly 
may  transmit  leprosy,  erysipelas,  anthrax,  smallpox  and  framboesia 
(Yaws).  Dr.  E.  P.  Felt  ('09)  writes,  "it  is  held  that  flies  may  under 
certain  conditions  convey  plague,  trachoma,  septicemia,  erysipelas, 
leprosy,  and  there  are  reasons  for  thinking  that  this  insect  (the  house 
fly)  may  possibly  be  responsible  for  the  more  frequent  new  cases  of 
smallpox  occurring  in  the  near  vicinity  of  a  hospital. ' ' 

The  experimental  evidence  against  this  insect  is  accumulating  rapidly, 
and  the  next  five  years  will  without  doubt  mark  the  addition  of  other 
diseases  to  the  already  appalling  number  ascribed  to  it,  and  further 
proof  with  regard  to  the  last  mentioned  diseases  as  yet  not  well  estab- 
lished. 

OBJECTIONS  MET. 

The  annihilation  of  a  species,  whether  complete  or  relative,  always 
brings  opposition  on  the  part  of  not  a  few  persons.  Few  ideas  are  more 
firmly  rooted  in  the  mind  of  the  average  man  or  woman  than  that  Nature 
has  brought  forth  nothing  that  is  useless  in  the  economy  of  the  human 
family.  It  is  time  and  again  asserted  that  this  or  that  insect,  though  it 
is  known  to  be  disease  transmitting,  must  be  good  for  something,  other- 


Bulletin  215]  THE  HOUSE  FLY  AND  HEALTH.  533 

wise  it  would  not  be  in  existence,  and  should,  therefore,  not  be  extermi- 
nated or  even  molested.  In  answer  to  this,  it  should  be  said  that  parasit- 
ism is  quite  certainly  an  acquired  habit.  Organisms  now  parasitic  have 
not  always  been  so,  though  they  can  not  now  well  exist  in  any  other  way. 
The  carelessness  of  man  (frequently  downright  uncleanliness)  results  in 
the  provision  of  a  favorable  environment  for  parasites.  Certainly  no 
one  would  contend  that  it  is  necessary  to  be  infested  with  lice,  or  even 
that  the  bed  must  be  infested  with  bedbugs.  Yet  the  principle  is  the 
same  relative  to  the  house  fly,  which  breeds,  as  has  been  pointed  out,  in 
excrement  and  refuse.  Again,  since  it  has  been  so  conclusively  proved 
that  certain  kinds  of  mosquitoes  transmit  malaria  and  others  yellow 
fever,  it  will  not  be  contended  that  it  is  a  breach  of  trust  against  Nature 
to  exterminate  the  mosquito,  and  thereby  the  causative  organism  of 
malaria  and  yellow  fever.  Some  have  said  that  the  house  fly  acts  as  a 
scavenger,  and  is,  therefore,  a  friend  of  man.  The  house  fly  is  the 
poorest  of  scavengers,  and  one  of  the  most  dangerous  of  man's  enemies — 
a  veritable  wolf  in  sheep's  clothing.  As  innocent  as  these  creatures  may 
appear,  the  evidence  as  revealed  by  scientific  methods,  shows  them  to  be 
monstrous  carriers  of  disease.  There  is  no  virtue  in  the  house  fly ;  there 
is  no  reason  why  it  should  continue  to  exist,  and  its  death  knell  is  being 
sounded  wherever  communities  care  for  the  health  of  the  individual. 
Dr.  E.  P.  Felt  ('09)  has  said  "our  descendants  of  another  century  will 
stand  in  amazement  at  our  blind  toleration  of  such  a  menace  to  life  and 
happiness." 

The  following  is  an  extract  from  a  letter  recently  received,  which 
illustrates  well  the  objections  frequently  raised : 

Dear  Sir  :  I  enclose  a  slip  that  I  cut  from  a  paper  saying  that  you  are  down  on 
the  poor  flies.  Now,  I  would  like  to  take  their  part.  I  have  known  them  nigh  on  to 
thirty  years,  and  I  never  knew  of  a  sickness  that  could  be  laid  to  them.  I  know  they 
make  a  lot  of  dirt,  spoil  picture  frames  and  such,  tickle  your  nose  in  the  morning  if 
you  don't  get  up,  but  they  make  a  nice  food  for  young  poultry.  *  *  *  Only  a  few 
years  back  they  were  considered  a  blessing,  as  they  eat  stuff  that  would  make  harm. 

*  *  *  they  spot  things,  make  a  lot  of  cleaning  that  keeps  folks  out  of  mischief. 
If  mosquitoes  or  fleas  harm  any  one,  it's  because  the  blood  is  out  of  order,  and  they 
had  better  look  to  it  and  mend  their  ways.     *     *     *     I  think  if  you  would  get  after 

them  of  your  size,  such  as and ,  they  are  parasites  that  do  more  harm 

than  insects  and  reptiles  combined.     *     *     *     so  if  you  want  to  scrap  go  after  them. 

*  *  *  this  torturing  poor  helpless  creatures  to  find  ways  to  prolong  lives  that  are 
worthless  *  *  *  we  all  must  die  some  way  *  *  *  hoping  you  will  let  the  flies 
and  little  things  alone.     *     *     * 

Unfortunately,  there  are  men  in  every  community  who  claim  to  be 
exponents  of  hygienic  progress,  but  who  oppose  any  agitation  of  this 
sort,  claiming  that  it  will  give  a  bad  name  to  their  city,  town  or  village. 
' '  Why  people  will  think  this  must  be  a  dreadful  place  in  which  to  live. ' ' 
As  a  matter  of  fact,  such  men  belong  in  the  same  category  with  the 
farmer  who  asked  the  question  with  the  I 've-got-you-now  spirit,  "What 
will  our  chickens  do  without  maggots  if  you  exterminate  the  house  fly  1 ' ? 


53-i  UNIVERSITY   OF    CALIFORNIA— EXPERIMENT    STATION. 

A  sane  body  of  business  men,  such  as  compose  the  "Chamber  of  Com- 
merce" of  any  community  would  surely  not  begin  a  "house  fly  cam- 
paign" if  it  were  in  sympathy  with  such  individuals  as  we  have  just 
quoted. 

ESSENTIALS  OF  CONTROL. 

Methods  of  control  are  planned  along  the  lines  set  forth  by  the  study 
of  the  life  history  and  habits  of  the  insect.  The  more  familiar  we  are 
with  regard  to  these  two  factors,  the  better  equipped  are  we  to  cope  with 
the  problems  of  control.  The  most  vulnerable  point  in  the  life  history 
must  be  determined,  and  then  the  most  effective  insecticide  applied,  or, 
what  is  better,  the  most  useful  preventive  methods  employed  either  in 
the  elimination  of  the  breeding  place  of  the  insect,  or  the  protection  of 
the  same  by  mechanical  or  chemical  means  to  prevent  the  deposition  of 
eggs,  thus  producing  ultimately  the  local  annihilation  of  the  species. 

The  following  statements  are  taken  largely  from  a  publication  by  the 
author  (Herms,  '09  b)  on  "The  Essentials  of  House  Fly  Control," 
issued  by  the  Berkeley  (Cal.)  Board  of  Health. 

The  house  fly  can  be  controlled  without  question.  This  is  demon- 
strated by  the  scarcity  of  flies  in  localities  where  cleanliness  about  stables 
and  houses  prevails  through  a  number  of  adjacent  city  blocks.  The 
work  of  control  can  be  greatly  furthered  by  the  individual  citizen; 
indeed,  the  California  State  Board  of  Health  in  Bulletin  No.  11  (1909), 
makes  the  following  statements:  "This  work  can  be  done  only  by  a 
united  effort.  The  citizen  must  do  the  work,  and  should  do  it  willingly, 
but,  if  negligent,  the  strong  hand  of  the  law  should  compel  it. ' '  The 
citizen  must,  however,  have  instruction  in  the  matter  since  there  is  the 
greatest  ignorance  relative  to  the  life  history  and  development  of  the 
house  fly  and  disease  transmitting  insects  in  general.  The  writer  finds 
that  this  ignorance  is  as  prevalent  among  the  educated  as  among  the 
uneducated. 

The  main  facts  pertaining  to  development  and  habits  indicate  the  most 
desirable  control  measures  to  be  pursued.  If  more  than  95  per  cent  of 
our  house  flies  develop  in  the  manures  of  horses,  and  there  is  no  question 
that  this  is  true,  and  the  rest  in  kitchen  refuse,  garbage  and  excrement 
of  man,  the  point  of  attack  is  clearly  outlined. 

The  open  manure  pile  must  be  abolished  and  stables  must  be  kept 
clean.  House  flies  breed  in  large  numbers  in  the  cracks  of  the  stable  and 
stall  floors,  where  manure  falls  between.  This  calls  for  the  use  of  cement, 
or  other  tight  floor  with  proper  provision  for  drainage.  Receptacles 
containing  kitchen  refuse  must  be  kept  tightly  closed  to  prevent  the 
female  fly  from  depositing  her  eggs  there. 

Permanent  preventive  measures  will  always  be  far  less  expensive  in 
the  end,  and  also  very  much  more  effective  than  the  use  of  temporary 


Bulletin  215] 


THE    HOUSE    FLY   AND    HEALTH. 


535 


methods  in  the  form  of  insecticides,  which  must  be  applied  repeatedly 
with  continuous  expenditure  of  time,  labor  and  money.  Domesticated 
animals  are  necessary  in  our  present  civilization,  but  the  methods  of 
disposing  of  manures  and  caring  for  stable  sanitation  has  remained  in 
most  cases  where  it  was  a  century  or  two  ago.  Where  many  horses  are 
stabled,  a  closet  to  receive  manures  can  be  built  at  a  small  cost.  This 
closet  must  be  kept  closed,  except  when  the  offal  is  being  placed  therein 
and  when  it  is  being  removed.  The  closet  may  be  built  in  one  corner 
(preferably  a  dark  one)  of  the  stable,  with  a  small  screened  door  through 
which  the  manure  is  thrown  when  cleaning  the  stalls  (providing  also 


Fig.  15. — Type  of  manure  closet  used  in  connection  with  the  University  of  Cali- 
fornia horse  stables.  This  receptacle  would  have  been  far  more  effective 
had  it  been  built  in  the  form  of  a  lean-to,  connecting  directly  with  the  stables 
by  means  of  a  small  screened  door,  thus  dispensing  with  the  open  outside  lid. 

for  ventilation),  and  an  outer  door  giving  access  to  clean  out  the  closet 
once  or  twice  a  week.  A  photograph  of  a  manure  closet  adjoining  one 
of  the  university  barns  is  shown  in  Fig.  15.  Such  a  closet  may  be  built 
in  the  form  of  a  shed  to  the  stable,  connecting  therewith  by  means  of  a 
screened  door  as  above,  or  the  closet  may  take  the  form  of  a  screened 
pit  in  the  darkest  corner  of  the  stable.  The  darkness  will  help  to  keep 
away  the  flies  also.  The  floors  of  these  closets  or  bins  should  be  tight 
so  as  to  prevent  seepage  of  the  manure  outside.  A  form  of  manure  pit, 
not  so  practical,  however,  as  the  above,  constructed  of  concrete,  is  shown 
in  Fig.  16 ;  a  form  used  in  the  Berkeley  Fire  Department  houses.    Where 


536  UNIVERSITY   OF    CALIFORNIA— EXPERIMENT    STATION. 

only  one  horse  is  stabled,  the  manure  may  be  conveniently  placed  in 
ordinary  garbage  cans  and  stamped  down,  or  in  tight  barrels  covered 
with  a  well  fitting  lid  or  wire  screen. 

A  very  serious  objection  to  several  of  these  bins  may  be  raised,  in 
that  the  wide  open  door  provides  access  to  the  flies  during  the  time 
manure  is  being  thrown  in,  and  once  inside  the  flies  deposit  their  eggs 
and  development  proceeds.  Thus,  where  the  contents  of  the  bin  is  not 
emptied  at  least  once  a  week,  and  then  perhaps  not  thoroughly  scraped 
out,  a  veritable  breeding  cage  results.  Obviously,  this  can  be  remedied 
by  frequent  and  careful  removal  of  manure  from  the  bin,  but  the  most 
satisfactory  way  is  to  construct  a  shed  or  lean-to,  as  already  mentioned, 


Fig.  16. — Photograph  of  a  concrete  manure  bin  constructed  at  one  of  the 
local  fire  department  houses.  Removal  of  the  manure  is  rendered 
difficult  because  it  must  be  lifted  out.  The  heavy  metal  lid  is  also 
inconvenient. 

with  only  a  small  opening  through  which  the  manure  is  thrown.  This 
opening  should  be  near  the  darker  end  of  the  stable  and  should  be 
screened. 

The  object  of  all  this  procedure  is  to  prevent  the  deposition  of  eggs 
by  the  flies  on  the  manure  or  other  offal  which  is  to  provide  food  for  the 
young.  On  the  ranch  it  is  often  possible  and  certainly  advisable  to 
remove  the  stable  manures  every  morning,  by  merely  backing  a  cart  to 
the  stable  door  and  depositing  therein  the  material  and  hauling  it  to 
the  field  at  once,  where  it  is  scattered.  The  manure  should  in  all  cases 
be  scattered  upon  the  field  and  not  be  allowed  to  accumulate  there  in 
heaps.     Thinly  scattered  manure  does  not  favor  the  breeding  of  flies 


BULLETIN  215]  THE   HOUSE   FLY   AND   HEALTH.  537 

because  of  lack  of  moisture.  Farmers  and  gardeners  who  wish  to  use 
decayed  manure  for  fertilizing  purposes  should  screen  the  heaps  until 
the  decaying  process  is  well  under  way,  when  fly  breeding  will  be 
reduced  to  a  minimum.  Stable  yards  and  empty  town  lots  used  for 
horses  are  a  source  of  many  flies.  Here  the  droppings  from  the  horses 
accumulate  and  are  kept  moist  by  the  urine  from  these  animals,  thus 
affording  good  breeding  places.  The  stable  yard  and  town  lot  used  for 
horses  must  not  be  overlooked  in  the  campaign  against  the  house  fly. 
Merely  sweeping  up  the  manure  with  a  broom,  or  superficial  shoveling 
without  scraping  up  the  loose  earth,  will  not  remedy  the  matter  greatly. 
It  must  be  borne  in  mind  that  when  the  larvae  have  fed  sufficiently  for 
full  growth,  a  period  of  four  or  five  days  after  hatching  from  the  eggs, 
they  crawl  into  the  loose  earth  underneath  the  manure  pile  (often  great 
pockets  of  larvae  may  be  found  thus),  or  they  wander  to  loose  debris  in 
the  immediate  vicinity,  many,  of  course,  remain  in  the  manure  pile  to 
complete  their  life  cycle.  Thousands  of  pupae  (recognized  as  chestnut 
colored,  barrel-shaped  individuals)  were  taken  by  the  writer  in  one 
instance  from  underneath  a  platform  leading  into  the  stable.  Thus, 
when  cleaning  up,  these  conditions  and  situations  must  be  taken  into 
account. 

Human  excrement,  if  left  uncovered,  furnishes  another  good  breeding 
ground  for  the  house  fly  (Howard,  '00).  The  dung  in  open  privies 
should  be  treated  thoroughly  with  ' '  chloride  of  lime, ' '  or  even  an  ounce 
of  kerosene  will  serve  well;  either  must  be  applied  at  intervals  of  three 
or  four  days  at  the  height  of  the  season.  Indiscriminate  defecation  in 
alleyways  and  little  frequented  situations  should  be  considered  a  misde- 
meanor punishable  by  a  heavy  fine,  for  the  reason  that  house  flies  breed 
also  in  human  excrement  and  especially  because  of  the  very  great  danger 
of  infection  by  means  of  flies.  In  communities  where  there  is  no  sewer 
system,  the  "dry  earth"  closet  is  most  satisfactory  and  should  be 
required  by  ordinance. 

Unused  brewer's  grains  and  mashes,  when  dumped  as  waste  in  the 
field  or  on  the  premises,  afford  a  famous  place  for  the  fly  to  develop. 
Oftentimes  this  is  used  as  feed  for  cattle,  and  what  is  left  over  is  simply 
dumped  on  to  the  field.  Often  this  waste  food  is  the  greatest  source  of 
flies  around  dairies. 

Guinea  pig  pens  and  rabbit  pens  may  become  prolific  breeders  of  flies 
if  they  are  not  carefully  cleaned. 


538  .   UNIVERSITY    OF    CALIFORNIA— EXPERIMENT    STATION. 


INSECTICIDES. 

FLY  LARVAE  IN  MANURE  PILES. 

Manure  piles  and  other  offal  already  infested  with  fly  larvae  should  be 
treated  with  an  insecticide  before  removal  in  order  to  kill  the  developing 
generation.  The  purchase  of  insecticides  for  continuous  use  would  be 
a  matter  of  no  small  cost,  especially  because  of  the  tenacity  of  life  shown 
by  fly  larvae  and  the  consequent  strength  of  insecticide  necessary  to  kill 
them.  Ordinary  applications  of  the  usual  insecticides  prove  of  no  avail. 
The  cheapest,  and  at  the  same  time  most  effective,  preparations  must  be 
applied  in  strengths  two  to  five  times  that  which  is  useful  against  other 
insects,  and  furthermore  the  larvae  can  not  be  easily  reached  buried  as 
they  are  in  the  bedding  and  offal.  In  the  face  of  these  conditions  the 
more  reliable  and  really  simpler  methods  mentioned  above  are  recom- 
mended. 

Chemicals  used  to  destroy  the  larvae  may  be  roughly  divided  into  two 
classes,  viz.,  (1)  contact  poisons,  and  (2)  stomach  poisons.  To  the  first 
class  belong  such  preparations  as  kerosene  and  cresol,  also  chloride  of 
lime.  To  the  second  class  belong  the  arsenicals  represented  by  arsenate 
of  lead  and  paris  green. 

Where  the  manure  pile  can  be  spread  out  to  a  depth  of  about  half  a 
foot  it  may  be  drenched  with  a  distillate  petroleum,  which"  possesses  a 
high  flash  point,  i.  e.,  does  not  ignite  easily,  and  has  the  necessary  insecti- 
cidal  property.  The  petroleum  oils  sold  as  proprietary  compounds  on  the 
market  as  ' '  Miscible  Oils, "  "  Spray  Emulsions, ' '  and  the  like,  should  be 
applied  at  the  rate  of  one  part  of  the  oil  to  ten  parts  of  water.  If 
kerosene  oils  of  a  low  flash  point  are  used  about  stables  and  outbuildings 
the  danger  from  fire  must  be  considered. 

The  larvae  can  also  be  destroyed  by  a  compound  made  in  the  following 
manner  and  diluted  at  the  rate  of  one  part  of  the  compound  to  twenty 
of  water.  Great  care  should  be  exercised  in  the  preparation  and  use  of 
this  insecticide,  since  it  is  corrosive  and  poisonous. 

Formula:  Dissolve  one  half  pound  caustic  potash  in  one  half  pint  of 
water,  let  stand  several  hours  until  dissolved  and  cold ;  add  this  to  one 
quart  of  raw  linseed  oil  contained  in  an  earthenware  vessel,  stirring  the 
while,  and  repeat  the  stirring  process  at  intervals  of  about  one  hour  for 
from  four  to  five  hours,  then  let  stand  over  night.  This  process  will 
result  in  a  soap  to  which  must  now  be  added  slowly,  while  stirring, 
one  and  a  quarter  quarts  of  commercial  cresol,  which  will  gradually 
dissolve  the  soap.  Three  or  four  days  may  be  necessary  to  effect  com- 
plete solution.    For  use,  this  compound  must  be  diluted  at  the  rate  of 


Bulletin  2151  THE  HOUSE  FLY  AND  HEALTH.  539 

one  part  to  thirty  of  water.  The  quantity  given  above  will  produce  from 
12  to  15  gallons.  Apply  to  the  manure  pile  or  garbage.  Poultry  must 
not  be  permitted  to  feed  upon  the  larvae  thus  treated.  (This  liquid,  used 
at  the  rate  of  one  part  to  one  hundred  parts  of  water,  is  also  serviceable 
as  a  germicide  applied  as  a  spray  about  poultry  houses.4) 

Chloride  of  lime  used  on  the  manure  pile  is  also  effective,  but,  like  the 
above,  is  expensive  when  used  in  proper  quantities. 

The  use  of  arsenical  poisons  has  not  been  thoroughly  tested  by  the 
writer;  indeed,  he  hesitates  to  recommend  these  materials  for  general 
use  because  of  the  danger  to  domesticated  animals  in  and  near  the  barn- 
yard, but  the  statements  by  Newstead  ('08)  are  here  repeated  as  an 
indication  that  the  matter  has  not  been  overlooked.  "The  application 
of  paris  green  (poison)  at  the  rate  of  two  ounces  to  one  gallon  of  water 
to  either  stable  manure  or  ashpit  refuse  will  destroy  99  per  cent  of  the 
larvae.  Possibly  a  smaller  percentage  of  paris  green  might  be  employed 
with  equally  good  results.  One  per  cent  of  crude  atoxyl  in  water  kills 
100  per  cent  of  fly  larvae.  The  application  of  either  of  these  substances 
might,  however,  lead  to  serious  complications,  and  it  is  very  doubtful 
whether  they  could  be  employed  with  safety. ' ' 

Tobacco  decoctions  have  been  tried  in  various  strengths  without  suc- 
cess; indeed,  the  fly  larvae  seemed  to  thrive  in  the  most  concentrated 
solutions. 

INDOOR  WORK — THE  ADULT  FLY. 

The  adult  female  flies  should,  wherever  possible,  be  prevented  from 
depositing  their  eggs  by  the  application  of  methods  already  described. 
Because  of  the  great  disease  transmitting  powers  of  the  flies  they  should 
be  kept  away  from  human  food.  Screens  must  continue  to  be  used  until 
the  community  as  a  whole  learns  to  apply  the  simple  remedies  to  exter- 
minate the  fly,  when  screens  will  no  longer  be  needed,  and  that  time  is 
not  far  off.  The  use  of  poisonous  (arsenical,  etc.)  preparations  upon 
which  the  flies  may  feed  is  not  recommended,  inasmuch  as  the  poisoned 
insects  often  drop  into  foods,  and,  what  is  more  important,  many  of  these 
preparations  are  a  menace  to  human  life,  especially  to  innocent  children. 
Sticky  fly  paper,  and  certain  traps,  while  disagreeable,  still  serve  a  good 
purpose.  Good  repellents  of  prolonged  effectiveness  are  still  wanting; 
experiments  with  a  series  of  essential  oils  show  that  oil  of  lavender  and 
oil  of  geranium  have  a  limited  effect  when  placed  in  shallow  vessels  on 
the  dining-room  table,  for  example. 

For  indoor  spraying  it  is  highly  desirable  that  the  insecticide  have  the 
following  attributes:  (1)  Non-poisonous  to  higher  animals,  including 
man;  (2)  non-corrosive  to  higher  animals,  including  man;  (3)  effective 
as  a  germicide  as  well  as  an  insecticide;  (4)  cheap;  (5)  non-repulsive 
odor  to  man.    Another  attribute:  (6)  repellent,  would  add  much  to  its 

*Maine  Agricultural  Experiment  Station  Bulletin  No.   165. 


540  UNIVERSITY   OF    CALIFORNIA EXPERIMENT    STATION. 

value.  Numerous  sprays  scoring  from  one  to  three  points  were  experi- 
mented with,  but  in  all  cases  the  effectiveness  was  more  pronounced  on 
blow  flies  than  on  the  house  fly,  and  in  all  cases  the  labor  involved  was 
not  inconsiderable. 

As  already  referred  to,  the  use  of  fly  poisons  is  objectionable  for  the 
reason  that  flies  are  liable  to  fall  into  food  or  the  poison  itself  might  be 
drunk  by  children,  with  possibly  fatal  results.  The  writer  has  found 
(as  already  suggested  by  others)  that  formaldehyde,  properly  used, 
forms  a  very  good  substitute  for  arsenical  or  cobalt  poisons.  Various 
dilutions  and  combinations  were  used,  but  a  2  per  cent  strength  when 
sweetened  somewhat  with  sugar  or  honey  (or  even  without  sweetening) 
proved  most  desirable.  Formaldehyde  is  inexpensive  when  used  as 
indicated,  and  has  the  added  advantage  that  it  is  not  poisonous  to  man 
in  weak  concentrations,  and  may,  therefore,  be  used  with  impunity  in 
this  form  around  food.  It  is  also  one  of  the  most  powerful  germicides 
known,  and  is  not  injurious  to  delicate  fabrics.  Formaldehyde  as  pur- 
chased at  the  drug  store  is  in  about  a  40  per  cent  solution  and  should 
be  diluted  with  water  down  to  about  2  per  cent  (add  about  twenty  times 
as  much  water).  The  solution  should  be  placed  in  shallow  vessels  on 
the  window  sills,  on  the  table  or  in  show  windows.  It  is  not  an  easy 
matter  to  control  the  fly  in  a  dining-room  where  there  is  plenty  of  liquid 
material  for  food  and  drink,  such  as  water,  milk,  sweets,  etc.,  but  when 
this  can  be  removed  or  covered  up  in  the  evening  and  the  dishes  of 
formaldehyde  then  put  in  place,  the  flies  will  drink  this  the  first  thing  in 
the  morning  and  the  end  will  be  accomplished  much  more  readily.  One 
is  here  taking  advantage  of  the  fact  that  the  fly  seeks  something  to  drink 
early  in  the  morning. 

Various  fumes  created  by  burning  one  or  the  other  of  the  following 
materials  will  stupefy  the  flies — pyrethrum  power  (Persian  pyrethrum 
or  Chrysanthemum  cineraria  folium),  Jamestown  weed  leaves  (dried) 
(Datura  stramonium)  mixed  with  crystals  of  saltpetre.  The  fly-fighting 
committee  of  the  American  Civic  Association  recommends  the  following : 
"Heat  a  shovel,  or  any  similar  article,  and  drop  thereon  20  drops  of 
carbolic  acid ;  the  vapor  kills  the  flies. ' ' 

OTHER  PRECAUTIONS. 

It  is  highly  important  that  sick  rooms  should  be  well  screened, 
especially  in  case  of  transmissible  diseases.  For  the  protection  of  the 
outside  world  any  flies  that  chance  to  find  their  way  inside  after  the  best 
precaution  has  been  exercised  should  be  killed  to  prevent  their  possible 
escape.  Pus  rags,  bandages,  sputum,  cloths,  and  the  like,  should  not  be 
carelessly  thrown  into  the  open  garbage  barrel  where  flies  freely  congre- 
gate.   It  may  seem  unnecessary  to  even  mention  these  simple  sanitary 


BULLETIN  2151  THE   HOUSE   FLY    AND    HEALTH.  541 

measures,  but  the  writer  has  seen  the  grossest  neglect  in  matters  of  this 
kind,  even  where  better  judgment  should  have  prevailed. 

THE  COMMUNITY- WIDE  CAMPAIGN. 

To  carry  out  the  suggested  permanent  preventive  measures  and  other 
methods,  a  community  should  to  begin  with  have  an  appointed  staff  of 
instructed  inspectors,  the  number  varying  with  the  size  of  the  com- 
munity ;  four  capable  men  working  in  pairs  can  cover  considerable  terri- 
tory very  well.  After  the  primary  steps  have  been  taken,  the  number 
can  be  reduced  to  the  regular  number  of  sanitary  inspectors,  provided 
they  know  their  business.  No  community  should  be  without  regular, 
instructed  sanitary  inspectors  under  the  direction  of  the  board  of 
health.  The  position  of  sanitary  inspector  should  carry  with  it  some 
dignity,  and  should  be  filled  by  men  instructed  in  practical  hygiene, 
including  a  fair  knowledge  of  medical  entomology,  inasmuch  as  the 
importance  of  insects  in  their  relation  to  disease  transmission  is  rapidly 
gaining  ground. 

The  author's  interest  in  " flies"  from  a  scientific  standpoint  dates 
back  some  eight  or  nine  years,  during  which  time  he  has  been  collecting- 
data  and  carrying  on  specific  investigations,  a  portion  of  which  has  been 
published,  as  already  pointed  out. 

During  the  winter  of  1908-1909,  the  writer  accompanied  the  Southern 
Pacific  demonstration  train  on  several  trips  through  California,  lectur- 
ing on  the  general  topic  of  medical  entomology,  but  agitating  especially 
the  question  of  house  fly  control  and  mosquito  control.  The  interest 
that  this  awakened  was  evidenced  by  many  letters  of  commendation,  and 
was  marked  by  some  effort  to  carry  on  the  work  by  individuals,  but  the 
importance  of  community  effort  was  at  that  time  really  not  properly 
considered  and  recognized.  However,  in  April,  1909,  the  following 
letter  was  received  from  the  Secretary  of  the  Berkeley  Chamber  of 
Commerce : 

Berkeley,  Cal.,  April  8.  1909. 

Dear  Sir  :  Knowing  that  you  are  interested  in  an  attempt  to  suppress  the  house 
fly  nuisance,  it  is  my  desire  to  enlist  your  aid  for  the  relief  of  Berkeley. 

This  office  is  located  between  two  livery  stables  that  breed  myriads  of  flies.  The 
proprietors  are  not  to  blame,  as  they  doubtless  would  cooperate  to  abate  the  nuisance. 
There  are  other  stables  that  are  similarly  prolific.  You  can  instruct  the  owners  of 
stables  how  to  apply  a  destroying  agency.  These  flies  if  left  undisturbed  will  scatter 
throughout  the  city  to  the  detriment  of  the  public  health.  I  respectfully  appeal  to 
you  to  give  this  matter  your  attention,  knowing  that  the  people  will  gratefully  acknowl- 
edge their  indebtedness  if  afforded  relief. 

In  answer  to  this  letter  an  outline  of  campaign  was  submitted,  which 
was  reported  upon  by  the  secretary,  viz. : 

At  a  conference  held  at  the  rooms  of  the  Berkeley  Chamber  of  Commerce  last 
evening  it  was  resolved  to  begin  a  campaign  against  the  pestiferous  insects  that 
usually  come  with  the  summer  season.     The  campaign  will  be  carried  on  under  the 

3— Bul.  215 


542  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

united  efforts  of  the  Berkeley  Board  of  Health  and  the  assistant  professor  in  ento- 
mology, University  of  California,  the  latter  to  be  assisted  by  more  than  twenty 
students,  who  will  be  appointed  inspectors.  These  students  wlil  be  appointed  as 
deputy  sanitary  inspectors,  and  their  work  in  the  field  will  be  devoted  to  discovering 
and  suppressing  places  that  if  left  uncorrected  would  become  breeding  places  for  flies, 
mosquitoes  and  other  pestiferous  insects. 

Upon  proper  showing  any  objectionable  place  will  be  declared  a  nuisance,  and  the 
owners  will  be  required  to  abate  said  nuisance. 

Dr.  J.  J.  Benton,  Berkeley's  Health  Officer,  and  the  other  members  of  the  Board 
of  Health,  are  unanimous  in  commending  the  campaign,  and  declare  that  they  will 
lend  all  aid  in  their  power  to  rid  Berkeley  of  these  pests.  Professor  Herms  will 
conduct  a  series  of  lectures  and  demonstrations  on  the  demonstration  plan,  to  show 
how  flies  and  other  insects  are  produced,  and  how  they  may  be  destroyed  or  prevented 
from  coming  into  existence.  It  is  proposed  to  make  Berkeley  a  spotless  town  in  this 
regard.    Berkeley  will  be  the  first  city  in  California  to  take  such  a  step  as  this. 

Outline  of  plan  : 

1.  Educational  lectures  and  demonstrations  by  Professor  Herms  at  the  Chamber 
of  Commerce  rooms.     Newspaper  agitation  and  discussion. 

2.  Cooperation  of  Board  of  Health.  To  declare  breeding  places  of  flies  and  mos- 
quitoes a  nuisance,  and  giving  moral  and  legal  indorsement. 

3.  Appointment  of  instructed  inspectors.  These  are  students  in  medical  ento- 
mology. To  be  in  charge  of  Professor  Herms,  medical  entomologist.  This  is  a  new 
science  that  already  has  proved  its  value  to  the  medical  world.  The  inspectors  are 
to  make  careful  survey  of  stables,  barnyards,  pools,  dumps  where  flies  might  breed, 
and  will  be  vested  with  authority  to  give  notice  to  abate  nuisance.  They  will  be 
regularly  appointed  sanitary  inspectors,  with  legal  power  to  serve  in  that  capacity. 
They  will  give  advice  and  instruction  in  regard  to  getting  rid  of  flies.  Ninety-five 
per  cent  of  house  flies  come  from  horse  manure.  It  is  possible  to  eliminate  this 
source  of  breeding  almost  altogether.  With  ninety-five  per  cent  of  the  house  flies 
destroyed  or  prevented  from  coming  into  existence  the  fly  nuisance  will  be  about 
eliminated. 

4.  Direct  methods  of  control.  In  charge  of  medical  entomologist.  Application  of 
insecticides ;  directed  against :  first,  adult  insects  on  premises ;  second,  larvae  in 
process  of  development.  Manure  must  be  retained  in  fly-tight  receptacles,  and 
removed  once  a  week.  The  garbage  situation  will  be  investigated  and  report  made 
to  Board  of  Health. 

Each  inspector  was  supplied  with  printed  cards  of  the  following  form : 

Street   No. 

Name 


Disposal  of  Garbage Standing  Water 

Stables Condition Barrels 

Horses Pools    

Cattle Troughs 

Hogs Cess  Pools 

floats Vermin  (Insects,  etc.). 

Flies 

Cats   Fleas   

Rabbits    Cockroaches    

Guinea  Pigs Ants 

Poultry    Sundry 

Pigeons    Condition  of  Premises  _ 

(Over)   Sketch  of  Premises.  Nuisances   

Inspector  


Bulletin  215]  THE  HOUSE  FLY  AND  HEALTH.  543 

With  the  following  ordinances  (given  here  in  part),  together  with  the 
support  of  the  police  department,  the  campaign  slowly  but  surely  took 

shape : 

Ordinance  No.  523a. 

Regulating  the  depositing  of  dirt,  paper,  filth,  sweepings,  ashes,  manure,  garbage,  or 

filthy  water,  offal  or  other  refuse  matter  in  the  town  of  Berkeley. 

Be  it  ordained  by  the  Board  of  Trustees  of  the  town  of  Berkeley  as  follows: 
Section  1.  It  is  hereby  declared  to  be  unlawful  for  any  person  to  throw  or 
deposit  or  to  cause  or  to  permit  to  be  thrown  or  deposited  any  dirt,  paper,  filth, 
sweepings,  or  filthy  water,  offal,  straw,  wood,  stones,  earth,  manure,  refuse  matter 
or  rubbish  of  any  kind  whatever,  into  any  avenue,  street,  way,  lane,  alley  or  public 
ground  in  the  town  of  Berkeley. 

Sec.  2.  It  is  hereby  declared  to  be  unlawful  for  any  person  to  throw  into  or 
deposit,  or  permit  or  cause  to  be  thrown  into  or  deposited  upon  any  private  premises 
in  the  town  of  Berkeley,  except  in  covered  metal  or  metal  lined  boxes  or  barrels,  any 
garbage  or  filth,  or  refuse  matter. 

Sec.  4.  Any  violation  of  this  ordinance  shall  be  deemed  a  misdemeanor,  punish- 
able by  a  fine  not  exceeding  fifty  (50)  dollars.  The  judgment  imposing  the  fine  may 
provide  for  its  collection  by  imprisonment  in  the  county  jail  of  Alameda  County,  at 
the  rate,  in  the  manner  and  for  the  time  provided  by  law. 

Stable  Ordinance  No.  447a. 

Regulating  the  erection  and  maintenance  of  stables  in  the  town  of  Berkeley,   and 

providing  a  penalty  for  the  violation  of  said  ordinance. 

Be  it  ordained  by  the  Board  of  Trustees  of  the  town  of  Berkeley  as  follows: 
Sec.  3.  Where  the  premises  on  which  any  stable,  barn,  shed,  or  stall  is  main- 
tained in  which  any  horse,  mule,  or  cow  is  kept,  fronts  on  a  street  in  which  is  con- 
structed a  sewer,  the  following  requirements  shall  be  complied  with,  viz. :  The  drain- 
age from  all  single  and  box  .stalls  where  a  horse,  mule  or  cow  is  kept  or  housed,  must 
in  all  cases  be  connected  to  the  street  sewer.  The  floor  of  all  said  stalls  must  be 
made  impervious  to  water,  and  the  drainage  from  said  stalls  must  be  conducted  to 
the  sewer  either  in  tile  or  cement  gutters,  of  a  radius  of  not  less  than  two  inches. 
The  said  gutters  shall  discharge  into  a  3-inch  or  4-inch  trap  before  entering  the  main 
sewer.  The  trap  must  be  protected  in  all  cases  by  a  strainer  and  be  easy  of  access 
for  cleaning  purposes. 

Sec.  5.  All  stables,  sheds,  barns,  stalls,  corrals,  or  stable  yards  in  which  any 
horse,  mule  or  cow  is  kept  shall  be  thoroughly  cleaned  out  at  the  following  intervals 
of  time  :  Where  stables,  barns,  sheds,  stalls,  corrals,  or  stable  yards  exist,  they  shall 
be  cleaned  out  at  least  every  day.  The  manure,  offal,  soiled  straw  or  other  refuse 
matter  from  all  stables,  barns,  sheds,  stalls,  corrals,  or  stable  yards  shall  be  placed 
immediately  upon  removal  from  such  stable,  barn,  shed,  stall,  corral,  or  stable  yards 
in  closely  covered  metal  or  metal  lined  receptacles,  and  kept  covered  until  destroyed 
or  removed  from  the  premises.  The  contents  of  such  receptacles  shall  be  removed 
therefrom  and  disposed  of  at  least  twice  a  week. 

Sec.  6.  Any  violation  of  this  ordinance  is  declared  to  be  a  misdemeanor,  punish- 
able by  fine  of  not  less  than  twenty-five  ($25.00)  dollars,  and  not  exceeding  one 
hundred  and  fifty  ($150.00)  dollars.  Each  day's  violation  of  the  provisions  of  this 
ordinance  shall  be  deemed  a  distinct  misdemeanor  and  be  punishable  as  such.  A 
judgment  imposing  a  fine  may  provide  for  its  collection  by  imprisonment  in  the 
county  jail  of  Alameda  County,  at  the  rate,  for  the  time,  and  in  the  manner  pro- 
vided by  law. 

The  Commissioner  at  the  head  of  the  Department  of  Public  Health 
and  Safety  met  with  the  Chamber  of  Commerce  and  the  writer,  inform- 
ing himself  fully  on  the  progress  of  the  campaign  and  the  methods, 
at  once  undertook  a  tour  of  inspection  about  the  city  seeing  the  situation 


544  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION. 

for  himself.  The  entire  police  force,  under  instructions  both  verbal  and 
written,  began  at  once  to  continue  the  work  of  sanitary  inspection, 
issuing  orders  to  abate  nuisances  wherever  found.  The  chief  of  police 
gave  his  heartiest  cooperation  throughout.     (See,  also,  Herms,  '09.) 

Communities  in  which  a  campaign  against  the  house  fly  has  been 
undertaken  with  determination  to  win  have  shown  that  the  fly  can  be 
controlled.  Sanitary  laws  must  be  enacted  and  rigidly  enforced  without 
fear  or  favor.  The  house  fly  can  be  controlled  without  question,  and 
without  great  labor  or  expense.  The  problem  is  simpler  than  many  are 
willing  to  admit,  but  it  requires  cooperation,  and  should  have  the  willing 
support  of  every  citizen.  Everybody  is  concerned,  and  everybody  will 
share  in  the  victory  and  share  in  the  saving  of  financial  and  vital  losses. 


Bulletin  215]  INDEX.  545 


INDEX. 


Page. 

American  Civic  Association's  recommendation 540 

Andre,  Dr.  Ch.,  investigations  of 531 

Annhilation  of  a  species,  objections  to 532 

Arsenical  poisons,  dangers  of 539 

Asiatic  cholera,   nature  of 532 

Bacteria  on  a  single  fly,  number  of 528 

Bacterial  diseases 515 

Bubonic  plague  preventable 514 

California  State  Board  of  Health 514 

Campaign  against  the  fly,  how  to  begin 541 

Cards  supplied  to  inspectors 542 

Children  molested  by  flies 530 

Chief  of  police  of  Berkeley 544 

Cholera  preventable 514 

Chloride  of  lime,  use  of 539 

Circumstantial  evidence  against  the  house  fly 524 

Commissioner  Department  Public  Health,  Berkeley 542 

Direct  method  of  disease  transmission 514 

Disease,  mosquitoes  and  flies  transmitters  of 513 

Eggs  of  house  fly,  time  required  for  hatching 519 

Eggs  of  house  fly,  where  laid 519 

Entomology,    study  of 513 

"Essentials  of  House  Fly  Control,"  extracts  from 534 

Experiments  in  the  laboratory 1 524 

Explanation  of  tables 522 

Felt,  Dr.  E.  P.,  statement  of 533 

Flies  as  carriers  of  tuberculosis 530 

Flies,  author's  interest  in 541 

Flies,  cases  of  sickness  plausibly  traceable  to 528 

Flies,  different  species  of 518 

Flies  during  Spanish-American  war 529 

Fly  traps,  expense  of 513 

Fly,  extract  from  letter  objecting  to  campaign  against  the 533 

Fly,  number  of  bacteria  on  a  single 528 

Formaldehyde,  a  substitute  for  poisons 540 

Formaldehyde,    how   to  use 540 

Form  of  manure  bin  in  use  by  Berkeley  Fire  Department 536 

House  fly,  the,  as  a  transmitter  of  dysentery 529 

House  fly  (Musca  domestica)   can  carry  germs 524 

House  fly,  a  dangerous  enemy  of  man 533 

House  fly,  distribution  of  sexes 521 

House  fly,  indirect  transmitter  of  disease 515 

House  fly,  life  history  of  the 518 

House  fly,  method  of  control 534 

House  fly  not  a  scavenger 533 

House  fly,  permanent  preventive  measures  for  controlling  the 534 

House  fly,  size  of  the 520 

How  to  begin  a  campaign  against  the  fly 541 

How  to  construct  closet  for  manure 535 

Howard,  Dr.  L.  O 513 

Human  food  should  be  protected  from  flies 539 

Indirect  methods  of  disease  transmission 515 

Insect  classification,  usual  method  of 515 

Insecticide,   formula  for 538 

Insecticides,  how  to  use 538 


546  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION. 

Page. 

Insecticides,  classes  of 538 

Insects,  importance  of  study  of 513 

Investigation,  justification  of 513 

Kerosene  on  manure  piles 538 

Larvae,  number  developed  in  average  manure  pile 519 

Letter  from  Berkeley  Chamber  of  Commerce 541 

Life  history  of  the  house  fly 518 

Lucilia  csesar  (flesh  fly) 520 

Lucilia  csesar,  life  cycle  of 520 

Malaria  preventable 514 

Malarial  fever  parasite,  the 523 

Medical  entomology 513 

Metamorphosis  of  house  fly 518 

Methods  of  controlling  the  house  fly 534 

Methods  of  disease  transmission 514 

Mosquitoes  and  flies  transmitters  of  disease 513 

Musca  domestica  (house  fly) 517 

Number  of  eggs  laid  by  house  fly 519 

Opposition  to  campaign  against  the  fly 532 

Ordinance  No.   523a 543 

Other  breeding  places  that  should  be  abolished 537 

Outline  of  campaign  against  the  fly 541 

Papers  relating  to  transmission  of  disease  by  insects 513 

Prevention  of  egg  laying  on  manure 535 

I'rotozoan  diseases 516 

Real  estate,  reduction  in  value  of 513 

Scavenger,  house  fly  not  a 533 

Screens,  necessity  of 513 

Screening  of  rooms  and  hospital  wards 532 

Serious  objection  to  some  forms  of  bin  for  containing  manure 536 

Sleeping  sickness  preventable 514 

"Sources  of  Bacteria  in  Milk"   (Esten  and  Mason) 526 

Stable  fly  direct  transmitter  of  disease 515 

Stable  Ordinance  No.  447a 543 

Stable  yards  and  town  lots 537 

Staphylococci  (suppurative  bacteria)  largely  carried  by  flies 532 

Stomoxys  calcitrans   (stable  fly) 517 

Sunlight  good  disinfectant 530 

Table  showing  relative  abundance  of  house  flies  and  distribution  of  sexes 521-522 

Tobacco  decoction  not  satisfactory 539 

Typhoid  bacilli  in  human  body,  where  found 528 

Typhoid  fever,  causative  organism  of 528 

Typhoid  fever  preventable 514 

Typhoid  transmission,  r61e  of  flies  in 528 

Tuberculosis,  how  contracted 530 

Yellow  fever  preventable 514 


Bulletin  215]  bibliography.  547 


BIBLIOGRAPHY. 

Andre.  Ch.,  '08 — Flies  as  Agents  in  the  Dissemination  of  Koch's  Bacillus.  Anti- 
Tuberculosis  Congress,  Washington,  D.  C,  Section  1.  (Printed  without  author's 
corrections. ) 

Esten,  W.  M.,  and  Mason,  C.  J.,  '08 — Sources  of  Bacteria  in  Milk,  Storrs.  Agri. 
Exp.  Sta.  Bull.,  No.  51,  pp.  65-109. 

Felt,  E.  P.,  '09  (a) — Control  of  Household  insects.  New  York  State  Museum 
Bulletin,  No.  129,  pp.  5-47. 

Felt,  E.  P.,  '09  (6) — The  Typhoid  or  House  Fly  and  Disease.  Reprinted  from 
N.  Y.  State  Museum  Bulletin  No.  134,  24th  Report  of  the  State  Entomologist,  190S. 
(Very  useful  bibliography  attached.) 

Herms,  W.  B.,  '07 — An  Ecological  and  Experimental  Study  of  Sarcophagidse, 
Journ.  of  Exp.  Zool.,  Vol.  LV,  No.  1,  pp.  45-83. 

Herms,  W.  B.,  '09  (a) — Recent  work  in  insect  behavior  and  its  economic  signifi- 
cance.    Journ.  of  Econ.  Ento.  Vol.  2,  No.  3,  pp.  223-230. 

Herms,  W.  B.,  '09  (6)— Essentials  of  House  Fly  Control.  Bulletin  Berkeley 
(Cal.)  Board  of  Health.     June  29,  9  pp. 

Herms,  W.  B.,  '09  (c)— The  House  Fly  Problem.  Pacific  Slope  Assoc,  of  Econ. 
Entomologists,  Bulletin  Card  No.  1. 

Herms,  W.  B.,  '09  (d) — Medical  Entomology,  Its  Scope  and  Methods.  Journ.  of 
Econ.  Ento.,  Vol.  2,  No.  4,  4  pp. 

Herms,  W.  B.,  '09  (e) — The  Berkeley  House  Fly  Campaign.  California  Journ. 
Tech.,  Vol.  14,  No.  2,  pp.  5-11. 

Herms,  W.  B.,  '10  (a) — Insects  as  they  relate  to  Rural  Hygiene.  California 
Cultivator,  pp.  35.  38,  39,  43,  Vol.  XXXIV,  No.  2. 

Herms,  W.  B.,  '10  (6)— Cattle  Flies  in  California.  California  Cultivator,  pp.  131. 
138.  Vol.  XXXIV,  No.  5. 

Herms,  W.  B.,  '10  (c) — Insect  Pests  as  they  Relate  to  Rural  Hygiene  with  special 
reference  to  control.  Proceedings  Thirty-sixth  Convention  of  the  California  State 
Fruit  Growers,  pp.  160-167. 

Herms,  W.  B.,  '10  (d) — How  to  control  the  Common  House  Fly.  California 
State  Board  of  Health  Bulletin,  pp.  269-277,  Vol.  5,  No.  11. 

Herms,  W.  B.,  '10  (e)— Fight  the  Fly,— Why,— When,— How.  Bulletin  Berkeley 
(Cal.)  Board  of  Health. 

Herms.  W.  B.,  '11 — The  Photic  Reactions  of  Sarcophagi  Flies,  especially  Lucilia 
Caesar  Linn,  and  Calliphora  vomitoria  Linn.  Jour,  of  Exp.  Zool..  Vol.  X.  No.  2, 
pp.  167-226. 

Herrick,  Glenn  W.,  '03 — The  Relation  of  Malaria  to  Agriculture  and  other  indus- 
tries of  the  South.     Pop.  Sc.  Mo.,  Vol.  LXII  (April),  pp.  521-25. 

Hewitt.  C.  Gordon,  '07 — The  Structure,  Development,  and  Binomics  of  the  House 
Fly.  Musca  domestica,  Part  1.  The  Anatomy  of  the  Fly.  Quart.  Journ.  Micro. 
Soc.  Vol.  51,  pp.  395-448. 

Howard,  L.  O.,  '00 — A  Contribution  to  the  Study  of  the  Insect  Fauna  of  Human 
Excrement.     Proc.  Wash.  Acad,  of  Sciences,  Vol.  II,  Dec.  28,  pp.  541-604. 

Howard,  L.  O.,  '06 — House  Flies.  U.  S.  Department  of  Agric,  Bureau  of  Ento.. 
Circ.  No.  71,  Rev.  Ed.,  10  pp. 

Howard,  L.  O.,  '09 — Economic  Loss  to  the  people  of  the  United  States  through 
insects  that  carry  disease.  U.  S.  Dept.  of  Agric,  Bureau  of  Ento.  Bull.  No.  78, 
10  pp. 

Jackson,  Daniel  D.,  '08 — Pollution  of  New  York  Harbor  as  a  Menace  to  Health 
by  the  Dissemination  of  Intestinal  Diseases  through  the  Agency  of  the  Common 
House  Fly.     Report  to  the  Water  Pollution  Committee  of  New  York  City. 

Jordan,  Edwin  O.,  '08 — A  Text-book  of  General  Bacteriology.  Philadelphia, 
pp.  557. 


548  UNIVERSITY  OF  CALIFORNIA EXPERIMENT  STATION. 

King,  A.  F.  A.,  '83 — Insects  and  Disease,  Mosquitoes  and  Malaria.  Pop.  Sc.  Mo., 
Vol.  XXIII   (Sept.),  pp.  644-658. 

Leveran,  A.,  et  Mesnil,  F.,  '04 — Trypanosomes  et  Trypanosomiases.  Paris,  XI, 
417  pp. 

Lord,  Frederick,  '04 — Boston  Medical  and  Surgical  Journal  (Dec.  15)  (cited  by 
Howard,  '09). 

Muir,  Robert,  and  Ritchie,  James,  '07 — Manual  of  Bacteriology,  London  and  New 
York.     XXI,  605  pp. 

Newstead,  Robert,  '08 — Life-Cycle  and  Breeding  Places  of  the  Common  House  Fly 
(Musca  domestica,  Linn).  Annals  of  Tropical  Medicine  and  Parasitology,  Vol.  1, 
No.  4,  pp.  507-520.     6  plates. 

Nuttall,  G.  H.  F.,  '99 — On  the  role  of  Insects,  Arachnids  and  Myriapods  as  carriers 
in  the  spread  of  Bacterial  and  Parasitic  Diseases  of  Man  and  Animals.  A  Critical 
and  Historical  Study.  The  Johns  Hopkins  Hospital  Reports.  Vol.  VIII,  Nos.  1-2, 
155  pp. 

Packard,  A.  S.,  '74 — On  the  transformations  of  the  Common  House  Fly,  with  notes 
on  allied  forms.    Proc.  Boston  Soc.  Nat.  Hist.    Vol.  XVI,  pp.  136-150. 

Smith,  John  B.,  '09 — Our  insect  Friends  and  Enemies.     Philadelphia.     314  pp. 

Spillman  and  Haushalter,  '87 — Dissemination  du  bacille  de  la  tuberculose  par  Jes 
mouches.    Comp.  rend.  t.  CV,  No.  7,  pp.  352-353.     (Cited  by  Nuttall.) 

Veder,  M.  A.,  '9S — Flies  as  Spreaders  of  Disease  in  Camps.  New  York  Med.  Rec, 
Sept.  17,  pp.  429-430. 


STATION     PUBLICATIONS    AVAILABLE     FOR     DISTRIBUTION. 

REPORTS. 

1896.  Report  of  the  Viticultural  Work  during  the  seasons  1887-93,  with  data  regard- 

ing the  Vintages  of  1894-95. 

1897.  Resistant  Vines,  their  Selection,  Adaptation,  and  Grafting.     Appendix  to  Viti- 

cultural Report  for  1896. 

1902.  Report  of  the  Agricultural  Experiment  Station  for  1898-1901. 

1903.  Report  of  the  Agricultural  Experiment  Station  for  1901-03. 

1904.  Twenty-second  Report  of  the  Agricultural  Experiment  Station  for  1903-04. 


BULLETINS. 


Reprint. 
No.   128. 

133. 

147. 
149. 
151. 
153. 
159. 

162. 

165. 

167. 

168. 

169. 

170. 
171. 

172. 

174. 
176. 

177. 

178. 
179. 

180. 
181. 
182. 


183. 
184. 


185. 


Endurance  of  Drought  in  Soils  of 
the  Arid.  Region. 

Nature,  Value,  and  Utilization  of 
Alkali  Lands,  and  Tolerance  of 
Alkali.  (Revised  and  Reprint, 
1905.) 

Tolerance  of  Alkali  by  Various 
cultures. 

Culture  Work  of  the  Sub-stations. 

California  Sugar  Industry. 

Arsenical  Insecticides. 

Spraying  with  Distillates. 

Contribution  to  the  Study  of  Fer- 
mentation. 

Commercial  Fertilizers.  (Dec.  1, 
1904.) 

Asparagus  and  Asparagus  Rust 
in   California. 

Manufacture  of  Dry  Wines  in 
Hot  Countries. 

Observations  on  Some  Vine  Dis- 
eases in  Sonoma  County, 

Tolerance  of  the  Sugar  Beet  for 
Alkali. 

Studies    in    Grasshopper    Control. 

Commercial  Fertilizers.  (June 
30,  1905.) 

Further  Experience  in  Asparagus 
Rust  Control. 

A  New  Wine-cooling  Machine. 

Sugar  Beets  in  the  San  Joaquin 
Valley. 

A  New  Method  of  Making  Dry 
Red  Wine. 

Mosquito  Control. 

Commercial  Fertilizers.  (June, 
1906.) 

Resistant  Vineyards. 

The  Selection  of  Seed- Wheat. 

Analysis  of  Paris  Green  and 
Lead  Arsenic.  Proposed  In- 
secticide Law. 

The  California  Tussock-moth. 

Report  of  the  Plant  Pathologist 
to  July  1,  1906. 

Report  of  Progress  in  Cereal 
Investigations. 


No. 


186. 
187. 

188. 

189. 

190. 
191. 
192. 

193. 


194. 


195. 


197. 


198. 
199. 
200. 

201. 

202. 

203. 

204. 

205. 

206. 

207. 
208. 
209. 
210. 

211. 

212. 
213. 
214. 


The   Oidium   of  the  Vine. 

Commercial  Fertilizers.  (January, 
1907.) 

Lining  of  Ditches  and  Reservoirs 
to  Prevent  Seepage  and  Losses. 

Commercial  Fertilizers.  (June, 
1907.) 

The  Brown  Rot  of  the  Lemon. 

California  Peach  Blight. 

Insects  Injurious  to  the  Vine  in 
California. 

The  Best  Wine  Grapes  for  Cali- 
fornia ;  Pruning  Young  Vines  ; 
Pruning  the  Sultanina. 

Commercial  Fertilizers.  (Dec, 
11)07.) 

The  California  Grape  Root- 
Worm 

Grape  Culture  in  California; 
Improved  Methods  of  Wine- 
making  ;  Yeast  from  California 
Grapes. 

The  Grape  Leaf-Hopper. 

Bovine  Tuberculosis. 

Gum  Diseases  of  Citrus  Trees  in 
California. 

Commercial  Fertilizers.  (June, 
1908.) 

Commercial  Fertilizers.  (Decem- 
ber, 1908.) 

Report  of  the  Plant  Pathologist 
to  July  1,   1909. 

The  Dairy  Cow's  Record  and  the 
Stable. 

Commercial  Fertilizers.  (Decem- 
ber,   1909.) 

Commercial  Fertilizers.  (June, 
1910.) 

The  Control  of  the  Argentine  Ant. 

The  Late  Blight  of  Celery. 

The  Cream  Supply. 

Imperial  Valley  Settlers'  Crop 
Manual. 

How  to  Increase  the  Yield  of 
Wheat  in  California. 

California  White  Wheats. 

The    Principles   of   Wine-making. 

Citrus  Fruit  Insects. 


4— Bul.  215 


CIRCULARS. 


No.      1.  Texas   Fever. 

5.   Contagious  Abortion  in  Cows. 
7.  Remedies  for  Insects. 
9.  Asparagus  Rust. 

11.  Fumigation  Practice. 

12.  Silk   Culture. 

15.  Recent  Problems  in  Agriculture. 
What  a  University  Farm  is  For. 

Disinfection  of  Stables. 

Preliminary  Announcement  Con- 
cerning Instruction  in  Practical 
Agriculture  upon  the  University 
Farm,  Davis,  Cal. 

White   Fly  in   California. 

32.  White    Fly   Eradication. 

33.  Packing  Prunes  in  Cans.  Cane 
Sugar  vs.  Beet  Sugar. 

36.  Analyses    of    Fertilizers   for    Con- 
sumers. 
Instruction    in    Practical    Agricul- 
ture at  the  University  Farm. 
Suggestions  for   Garden   Work   in 
California  Schools. 
47.  Agriculture  in  the  High  Schools. 


19. 

29. 


30. 


39. 


46. 


No.   48.   Butter  Scoring  Contest,  1909. 
60.   Fumigating  Scheduling. 
51.  University  Farm  School. 

53.  Announcement   of   Farmers'    Short 

Courses   for    1910. 

54.  Some     Creamery      Problems     and 

Tests. 

55.  Farmers'  Institutes  and  University 

Extension  in  Agriculture. 

58.  Experiments  with  Plants  and  Soils 

in     Laboratory,     Garden,     and 
Field. 

59.  Tree      Growing      in      the      Public 

Schools. 

60.  Butter   Scoring  Contest,   1910. 

61.  University  Farm  School. 

62.  The  School  Garden  in  the  Course 

of  Study. 

63.  How     to     Make     an     Observation 

Hive. 

64.  Announcement   of   Farmers'    Short 

Courses  for  1911. 

65.  California   Insecticide   Law. 

66.  Insecticides  and  Insect   Control. 


